Editing Circle line (London Underground)

{{short description|London Underground line}}
{{Use dmy dates|date=February 2024}}
{{Use British English|date=January 2020}}
{{Infobox rail line
| name                            = Circle line
| logo                            = London flag boxes - Underground Circle line.svg
| logo_width                      = 250px
| logo_alt                        = 
| image                           = Au Morandarte Flickr S7 21330 on Circle Line, Aldgate (9672093333).jpg
| image_width                     = 250
| image_alt                       = A red S7 Stock train arriving at the clockwise platform at Aldgate station, with passengers waiting to board
| caption                         = A Circle line  [[S7 Stock]] train at [[Aldgate tube station|Aldgate]]
| type                            = [[Rapid transit]]
| system                          = [[London Underground]]
| start                           = Edgware Road
| end                             = Hammersmith
| mapcolour                       = Corporate Yellow (with black outline until 1990){{sfn|Leboff|Demuth|1999|p=50}}
| mapcolourlink                   = Tube map
| stations                        = 36
| ridership2                      = 141.627 million (2019){{efn|combined figures for Circle and Hammersmith & City lines}}<ref>{{cite web |title=London Assembly Questions to the Mayor |url=https://www.london.gov.uk/who-we-are/what-london-assembly-does/questions-mayor/find-an-answer/tube-usage-1|publisher=London Assembly |year=2022 |access-date=29 February 2024}}</ref> passenger journeys
| open                            = Infrastructure opened in stages between {{start date and age|1863|p=y}} and 1884; shown as a separate line on the Tube map from 1949
| lastextension                   = 13 December 2009
| character                       = Sub-surface
| depot                           = [[Hammersmith Depot|Hammersmith]]
| stock                           = [[S7 Stock]]
| linelength_km                   = 27
| tracklength_km                  = 
| gauge                           = {{Track gauge|sg|allk=on}}
| website                         = [http://www.tfl.gov.uk/ tfl.gov.uk]
| map_name                        = [[Transport for London]] {{nowrap|rail lines}}
| map                             = {{London rail lines}}
| map_state                       = collapsed
}}

The '''Circle line''' is a spiral-shaped [[London Underground]] line, running from [[Hammersmith tube station (Circle and Hammersmith & City lines)|Hammersmith]] in the west to [[Edgware Road tube station (Circle, District and Hammersmith & City lines)|Edgware Road]] and then looping around central London back to Edgware Road. The railway is below ground in the central section and on the loop east of [[Paddington tube station (Circle and Hammersmith & City lines)|Paddington]]. Unlike London's [[London Underground infrastructure#Subsurface versus deep-level tube lines|deep-level lines]], the Circle line tunnels are just below the surface and are of similar size to those on British main lines. Printed in yellow on the [[Tube map]], the {{convert|17|mi|km|adj=on}} line serves 36 stations, including most of [[London station group|London's main line termini]]. Almost all of the route, and all the stations, are shared with one or more of the three other sub-surface lines, namely the [[District line|District]], [[Hammersmith & City line|Hammersmith & City]] and [[Metropolitan line|Metropolitan]] lines. On the Circle and Hammersmith & City lines combined, over 141&nbsp;million passenger journeys were recorded in 2019.

The first section became operational in 1863 when the [[Metropolitan Railway]] opened the world's first underground line between Paddington and {{stn|Farringdon}} with wooden carriages and steam locomotives. The same year a [[Select committee (United Kingdom)|select committee]] report recommended an "inner circle" of lines connecting the London railway termini, and the Metropolitan District Railway (commonly known as the [[District Railway]]) was formed to build the southern portion of the line.

In 1871, services began between [[Mansion House tube station|Mansion House]] and [[Moorgate station|Moorgate]] via Paddington, jointly operated by the two companies. Due to conflict between the two companies it was not until October 1884 that the inner circle was completed. The line was electrified in 1905, and in 1933 the companies were amalgamated into the [[London Passenger Transport Board]]. In 1949, the Circle line appeared as a separate line for the first time on the Tube map. In 2009, the [[orbital (metro)|closed loop]] around the centre of London on the north side of the [[River Thames]] was broken at Edgware Road and extended west to become a spiral to Hammersmith.

Starting in 2015, the signalling system was upgraded as part of a programme to increase peak-hour capacity on the line. The six-car [[C Stock]] trains were replaced from 2012 to 2014 by new seven-car [[London Underground S7 and S8 Stock|S Stock]] trains.

==History==

===Origins===
{{Main|Metropolitan Railway|District Railway}}
{{Infobox UK legislation
| short_title           = Metropolitan and District Railways (City Lines and Extensions) Act 1879
| type                  = Act
| parliament            = Parliament of the United Kingdom
| long_title            = 
| year                  = 1879
| citation              = [[42 & 43 Vict.]] c. cci
| introduced_commons    = 
| introduced_lords      = 
| territorial_extent    = 
| royal_assent          = 
| commencement          = 
| expiry_date           = 
| repeal_date           = 
| amends                = 
| replaces              = 
| amendments            = 
| repealing_legislation = 
| related_legislation   = 
| status                = 
| legislation_history   = 
| theyworkforyou        = 
| millbankhansard       = 
| original_text         = 
| revised_text          = 
| use_new_UK-LEG        = 
| UK-LEG_title          = 
| collapsed             = yes
}}
[[File:High Street Kensington 1892.jpg|thumb|High Street Kensington station in 1892|alt=A black-and-white photograph of a railway station platform under a barrel roof. Several figures are visible, one standing wearing a top hat, a sign reads "WAIT HERE FOR THIRD CLASS".]]
In 1863, the [[Metropolitan Railway]], the world's first underground railway, opened in London between [[Paddington tube station (Circle and Hammersmith & City lines)|Paddington]] and [[Farringdon station|Farringdon]], connecting the [[Great Western Railway]]'s relatively remote terminus at Paddington with [[Euston railway station|Euston]] and [[London King's Cross railway station|King's Cross]] stations and [[City of London|the City]], London's financial district. In the same year, a [[Select committee (United Kingdom)|select committee]] report recommended an "inner circle" of railway lines connecting the London termini that had been built or were under construction. In the next year, the Metropolitan District Railway (commonly known as the [[District Railway]]) was formed to build and operate a railway from South Kensington to Tower Hill. The Metropolitan western extension from a new station at [[Paddington tube station (Bakerloo, Circle and District lines)|Paddington]] to [[South Kensington tube station|South Kensington]] opened in 1868. By May 1870, the District Railway had opened its line from West Brompton to Blackfriars via Gloucester Road and South Kensington, services being operated at first by the Metropolitan.{{sfn|Green|1987|pp=7–9}} In 1871, the District had built a terminus at [[Mansion House tube station|Mansion House]], and on 18 November 1876 the Metropolitan opened its terminus at [[Aldgate tube station|Aldgate]].{{sfn|Green|1987|pp=10–11}} Because of the conflict between the two companies, it took an act of Parliament, the '''{{visible anchor|Metropolitan and District Railways (City Lines and Extensions) Act 1879}}''' ([[42 & 43 Vict.]] c. cci) before further work was done on the inner circle.{{sfn|Green|1987|p=12}} In 1882, the Metropolitan extended its line from Aldgate to a temporary station at [[Tower of London tube station|Tower Hill]] and the District completed its line to [[Whitechapel station|Whitechapel]]. On 6 October 1884, the temporary station was replaced with a [[Mark Lane tube station|joint station]] and the inner circle was complete.{{sfn|Simpson|2003|pp=23–4}}{{sfn|Rose|2007}} The Metropolitan provided the clockwise, or "outer rail", trains; the District the "inner rail", or anti-clockwise.{{sfn|Bruce|1983|p=11}} Many breakdowns occurred, due to the unbalanced wear-and-tear inflicted upon the train and carriages caused by travelling in a single circular direction. Equally, services were further disrupted due to petty squabbles between the two rivals including an incident whereby the Metropolitan Railway forcibly removed (using three trains) the District Railway's parked carriages which had been chained to the track.<ref>{{cite book |last=Bextor |first=Robin |year=2013 |title=Little Book of the London Underground |location=Woking |publisher=Demand Media Limited |isbn=9781909217379 }}</ref>

===Other circle routes===
As well as the inner circle, other routes circumnavigated London, although these were not complete loops. From 1872, the [[L&NWR]] began an "[[Outer Circle (London)|outer circle]]" service from Broad Street to Mansion House via Willesden Junction and Earl's Court, diverting an earlier service that had run to Victoria; and the [[Great Western Railway|GWR]] began a "[[Middle Circle|middle circle]]" service from Moorgate to Mansion House via Latimer Road and Earl's Court. Both of these routes were cut back to Earl's Court: the "middle circle" in 1900 and the "outer circle" in 1909. The GWR service survived as a shuttle service from the Hammersmith & City line to Addison Road, now Kensington (Olympia), until 1940.{{sfn|Bruce|1983|p=11}}

The Midland Railway briefly ran a [[Super Outer Circle|super outer circle]] from St Pancras to Earl's Court from 1878 to 1880.{{sfn|Bruce|1983|p=11}} [[London Overground]] now runs services between Clapham Junction, Willesden Junction and Dalston Junction and between Dalston Junction and Clapham Junction.

===Electrification===
[[File:Experimental Train.jpg|thumb|The joint Metropolitan and District Railway experimental electric train that ran between Earl's Court and High Street Kensington in 1900|alt=A three-quarter black-and-white photograph of a train standing at a station, showing the end carriage with windows at the end]]
Wooden carriages were originally hauled by [[steam locomotive]]s leading to smoke-filled stations and carriages, unpopular with passengers. At the start of the 20th century, the District and Metropolitan were seeing increased competition in central London from the new electric underground tube lines and trams, and conversion to electric traction was seen as the way forward.{{sfn|Horne|2003|p=28}} Experiments were carried out on the Earl's Court to High Street Kensington section, and a jointly-owned six-carriage train began passenger service in 1900. Following this, an [[Alternating current|AC]] system was suggested, and this was accepted by both parties. However, the District was looking for a way to raise the finance needed and in 1901 found an investor, the American [[Charles Yerkes]]. He formed the [[Underground Electric Railways of London]] (UERL), and his experience in the United States led him to favour [[direct current|DC]], with [[third-rail]] pick-up similar to that in use on the [[City & South London Railway]] and [[Central London Railway]]. After arbitration by the [[Board of Trade]], the DC system was taken up, and the railways began electrifying the routes, using multiple-unit stock.{{sfn|Green|1987|p=25}}

The District and Metropolitan Railways bought different designs of [[electric multiple unit]]. Both had open saloons; the Metropolitan trains with gated ends, the District [[London Underground B Stock|B Stock]] with sliding doors in the middle of each car.{{sfn|Bruce|1983|pp=33,37}} When their introduction was attempted on 1 July 1905, a Metropolitan train overturned the third rail on the District Railway, requiring all Metropolitan trains to be modified before running again on the District lines. A fully electric service began on 24 September, initially with six-car trains, later reduced to four-car.{{sfn|Bruce|1983|p=40}} The Metropolitan trains were soon modified to enclose the gated end{{sfn|Bruce|1983|p=37}} and eventually to add sliding doors in the middle.{{sfn|Bruce|1983|p=39}} Trains were increased to five cars in 1918 and the Metropolitan introduced new stock in 1921, with three pairs of sliding double doors on trailer cars.{{sfn|Bruce|1983|p=71}} In 1926 the Metropolitan took over all inner circle workings except for three trains on Sundays.{{sfn|Bruce|1983|pp=40–41}}

===London Transport===
[[File:CO Stock at Barking.jpg|thumb|O Stock was used on the Circle line 1947–70. Here photographed at Barking in 1980.|alt=A three-quarter photograph of a red train O stock with sliding doors and flared sides, leaving Barking station bound for Ealing in 1980]]
[[File:Circle Line (old).svg|thumb|upright=1.65|The Circle line before the extension to Hammersmith in 2009]]
On 1 July 1933, the Metropolitan and the District Railways were amalgamated with other Underground railways, tramway companies and bus operators to form the [[London Passenger Transport Board]]. Metropolitan Railway electric multiple units were refurbished in 1934 at Acton Works to become eighteen five-car trains of [[London Underground Circle Stock|Circle Stock]], at first painted red and cream, later painted red all over to reduce costs. These trains included first-class accommodation,{{sfn|Bruce|1983|pp=76–77}} but this was downgraded in 1940.{{sfn|Green|1987|p=51}} From 1947, these were replaced by five-car trains of [[London Underground O and P Stock|O and P Stock]], with doors remotely operated by the guard, released by the transfer of [[London Underground F Stock|F Stock]] to the Uxbridge line.{{sfn|Bruce|1983|p=94}} The 1933 London Underground [[Harry Beck|Beck]] map shows a Metropolitan line north of {{stl|London Underground|High Street Kensington}} and {{stl|London Underground|Mark Lane}} stations and a District line south of these points.{{sfn|Green|1987|p=33}} On the 1947 map, the Metropolitan and District lines were shown together in the same colour{{sfn|Green|1987|p=54}} and two years later in 1949 the Circle line was shown separately on the map.<ref>{{cite web|url=http://homepage.ntlworld.com/clivebillson/tube/tube.html#1949|title=1949 tube map|access-date=5 March 2012|archive-date=15 August 2007|archive-url=https://web.archive.org/web/20070815041850/http://homepage.ntlworld.com/clivebillson/tube/tube.html#1949|url-status=dead}}</ref>

In 1959–1960, Circle line trains were increased to six cars, the same length as those operating on the Hammersmith & City line, and the stock of the two lines was integrated with maintenance concentrated at Hammersmith depot, allowing [[Neasden Depot|Neasden depot]] to concentrate on the new [[London Underground A60 and A62 stock|A Stock]].{{sfn|Bruce|1983|p=95}} Aluminium [[C Stock]] trains, with public address systems and originally unpainted, replaced these trains from 1970.{{sfn|Bruce|1983|p=114}} [[One person operation]] of the trains was proposed in 1972 but, due to conflict with the trade unions, was not introduced until 1984.<ref>{{cite book|last1=Croome|first1=Desmond F.|last2=Jackson|first2=Alan Arthur|title=Rails Through the Clay: A History of London's Tube Railways|year=1993|publisher=Capital Transport|page=468|isbn=978-1-85414-151-4}}</ref> In 2003, the infrastructure of the Circle line was partly privatised in a [[public–private partnership]], managed by the [[Metronet (British infrastructure company)|Metronet]] consortium. Metronet went into [[Administration (law)|administration]] in 2007 and the local government body [[Transport for London]] took over responsibilities.<ref>{{cite web |url=http://www.tfl.gov.uk/assets/downloads/london-underground-ppp-performance-report-2009-2010.pdf |title=PPP Performance Report |year=2010 |publisher=Transport for London |access-date=7 March 2012 |pages=7–8 |archive-date=26 April 2012 |archive-url=https://web.archive.org/web/20120426034334/http://www.tfl.gov.uk/assets/downloads/london-underground-ppp-performance-report-2009-2010.pdf |url-status=dead }}</ref>

On 7 July 2005, at about 08:50, [[7 July 2005 London bombings|bombs exploded]] on two Circle line trains. One was travelling between [[Liverpool Street station|Liverpool Street]] and Aldgate and the other was at [[Edgware Road tube station (Circle, District and Hammersmith & City lines)|Edgware Road]]. The bombs killed 15 people, including the two suicide bombers.<ref>{{cite news |url= http://news.bbc.co.uk/1/shared/spl/hi/uk/05/london_blasts/what_happened/html/edgware_rd.stm |title=7 July Bombings: Edgware Road |access-date=24 November 2012 |work=BBC News}}</ref><ref>{{cite news |url= http://news.bbc.co.uk/1/shared/spl/hi/uk/05/london_blasts/what_happened/html/aldgate.stm |title=7 July Bombings: Aldgate |access-date=24 November 2012 |work=BBC News}}</ref> Following the attacks, the whole of the Circle line was closed until 8 August.{{sfn|Day|Reed|2010|p=217}}

A day before a ban on drinking alcohol on public transport in London came into force, a party was held on 31 May 2008, mainly on the Circle line. Thousands of people attended and 17 were arrested by police due to disorderly behaviour, eventually causing several stations to be closed.<ref>{{cite news |title=Tube drinks party sparks mayhem |url= http://news.bbc.co.uk/1/hi/england/london/7429638.stm |work=BBC News |date=1 June 2008 |access-date=23 August 2012}}</ref>

===Extension===
Prior to 13 December 2009, Circle line trains travelled in both directions around a simple loop with 27 stations and {{convert|20.75|km|order=flip}} of track. In 2006, there were fourteen trains in service on the line with an interval between trains of {{fract|8|1|2}}&nbsp;minutes during peak hours and 8 minutes off-peak; the minimum running time around the circle off-peak was {{fract|51|1|2}}&nbsp;minutes,<ref>{{cite book | publisher=London Underground | title=Working Timetable No. 21, from 11 June 2006 | date=20 April 2006|pages=2–3}}</ref> although timetabled stops at stations extended this.{{efn|For example the 22:26 outer rail (clockwise) service from Aldgate was booked to arrive back at Aldgate at 23:22 after waiting at Gloucester Road (for {{fract|1|1|2}}&nbsp;minutes), Edgware Road ({{fract|2|1|2}}&nbsp;minutes) and Baker Street ({{fract|1|2}}&nbsp;minute).<ref>{{cite book  | publisher=London Underground | title=Working Timetable No. 21, from 11 June 2006 | date=20 April 2006|page=45}}</ref>}}

In December 2009, the Circle line was extended to include the Hammersmith & City route from Edgware Road to Hammersmith. Rather than continuously running around the circle, trains now travel from Hammersmith to Edgware Road, generally going around the circle once before terminating at Edgware Road, and returning via the same route; occasionally, trains may also continue clockwise through Edgware Road to additional stations. The change was made to improve reliability and increase the service frequency on the Hammersmith branch.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/england/london/7926242.stm|title=Circle Line extended to the west|work=BBC News|date=5 March 2009|access-date=24 November 2011}}</ref>

In March 2020, following the UK government's implementation of lockdown restricting all non-essential travel, the Circle line, along with the [[Waterloo & City line]], was suspended.<ref>{{Cite news |url= https://www.cityam.com/revealed-sadiq-khan-to-blame-for-tube-overcrowding-says-transport-watchdogs/ |title=Decision to cut Tube services caused overcrowding, say watchdogs |date=20 April 2020 |newspaper=City A.M. |location= London |access-date=23 April 2020}}</ref>

==Route==

===Map===
{{wide image|Circle line & London map.svg|700px|The route of the Circle line since 13 December 2009 and the [[London borough]]s it serves|center}}

===Railway line===
{{Circle Line RDT}}
The Circle line is {{convert|27|km|mi|order=flip}} long with 36 stations.<ref name="linefacts">{{cite web |url=http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/keyfacts/13165.aspx |title=Circle line facts |access-date=5 December 2012 |publisher=Transport for London |archive-date=1 January 2012 |archive-url=https://web.archive.org/web/20120101065103/http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/keyfacts/13165.aspx |url-status=dead }}</ref> Almost all of its track, and all of its stations, are shared with the other London Underground sub-surface lines: the [[Hammersmith & City line]] from Hammersmith to Liverpool Street; the [[Metropolitan line]] from just east of Baker Street to [[Aldgate tube station|Aldgate station]]; the main branch of the [[District line]] from [[Tower Hill tube station|Tower Hill station]] to Gloucester Road; and the Edgware Road branch of the District line from High Street Kensington to Edgware Road.<ref name="map" /> The only two sections of track which are not shared with any other lines are linking sections between Aldgate and Tower Hill, and between Gloucester Road and High Street Kensington. The line is electrified with a four-rail DC system: a central conductor rail is energised at {{Val|-210|u=V}} and a rail outside the running rail at {{Val|+420|u=V}}, giving a potential difference of {{Val|630|u=V}}.<ref name="Martin2012">{{cite book |author=Martin, Andrew |title=Underground, Overground: A Passenger's History of the Tube |url= https://books.google.com/books?id=vh3n5WD_YqsC&pg=PT137 |access-date=7 December 2012 |date=26 April 2012 |publisher=Profile Books |isbn= 978-1-84765-807-4 |pages=137–138}}</ref> The running rails are not electrified. Much of the {{convert|2|mi|35|chain|adj=on}} double track railway from the [[Hammersmith tube station (Circle and Hammersmith & City lines)|Hammersmith terminus]] to [[Westbourne Park station]] is on a {{convert|20|ft|adj=on}} high brick viaduct.{{sfn|Jackson|1986|p=38}}

East of Westbourne Park the line passes beneath the [[Great Western Main Line]] before resurfacing at [[Royal Oak tube station|Royal Oak station]] and running alongside the tracks of the main line to an island platform just north of the suburban platforms at [[Paddington station]].<ref name="map">{{cite web|url=http://cartometro.com/cartes/metro-london/|archive-url=https://web.archive.org/web/20200728161716/http://cartometro.com/cartes/metro-london/|url-status=dead|archive-date=28 July 2020|title=Detailed London Transport Map|access-date=23 November 2012|work=cartometro.com}}</ref> The line enters a cut and cover tunnel at the end of the platforms and meets the District line and the other end of the Circle line from Bayswater at Praed Street Junction before passing through Edgware Road station in a cutting. After [[King's Cross St Pancras station]] the line exits the tunnel before passing over the [[Ray Street Gridiron]] beneath which pass the [[City Widened Lines]] which are currently used by [[Thameslink]] services.<ref name="map"/>{{sfn|Jackson|1986|p=48}} The line continues underground after [[Farringdon station]]; there are bay platforms at [[Moorgate station]].<ref name="map"/>

After passing through Aldgate station, the terminus of the Metropolitan line, the line joins the District line shortly before Tower Hill; this part of the line includes stations on the [[Victoria Embankment]], on the north bank of the Thames, as far as Westminster station.<ref name="map"/> West of Gloucester Road station the line turns off the District main line to join the District line's Edgware Road branch just before High Street Kensington station.<ref name="map"/> In Bayswater the line is in a cutting, concealed from above by a façade of two five-storey houses at [[23-24 Leinster Gardens|Nos 23 and 24 Leinster Gardens]].{{sfn|Jackson|1986|pp=52–53}} Trains then call at the second Paddington station on Praed Street before rejoining the Hammersmith & City line at Praed Street junction and terminating at the four-platform Edgware Road station.<ref name="map"/>

==Services==
{{As of|December 2012}}, there are six trains per hour, calling at all stations,<ref name="TBL"/> requiring 18 trains in service.<ref name="linefacts"/> The journey from Edgware Road around the loop and continuing to Hammersmith takes 72 minutes off-peak.<ref name="TBL">{{cite web |url= http://journeyplanner.tfl.gov.uk/user/XSLT_SEL_STT_REQUEST?sessionID=0&language=en&mode=line&linePreSel=tfl:25:*&linePreSel=tfl:63:*|title= Hammersmith to Edgware Road Circle line timetable |publisher=Transport for London |access-date=9 December 2012}} In the Tube timetable - Tube station box select "Hammersmith (H&C Line)" and press ''Get Timetable''. Select Edgware Road timetable and then view timetable.</ref> Together with the Hammersmith & City line over 114&nbsp;million passenger journeys are made each year.<ref name="Almanac">{{cite web|url=http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/1592.aspx |title=Performance: LU Performance Data Almanac |publisher=[[Transport for London]] |year=2012 |access-date=17 January 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130214030201/http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/1592.aspx |archive-date=14 February 2013 }}</ref> Paddington and all stations on the loop are within Zone 1, with those on the line to Hammersmith in Zone 2.<ref>{{cite web |url= http://www.tfl.gov.uk/assets/downloads/standard-tube-map.pdf |title= Standard Tube Map |publisher= Transport for London |access-date= 8 December 2012 |archive-date= 26 June 2008 |archive-url= https://web.archive.org/web/20080626161335/http://www.tfl.gov.uk/assets/downloads/Standard-Tube-map.pdf |url-status= dead }}</ref>

Two trains per day run from Barking to Edgware Road via Victoria (as of February 2015).<ref>{{cite web|last=Elledge |first=Jonn |url=http://www.citymetric.com/transport/london-underground-why-are-circle-line-trains-showing-whitechapel-1544 |title=London Underground: Why are Circle line trains showing up at Whitechapel? |publisher=CityMetric |date=2 November 2015 |access-date=14 July 2017}}</ref>

=== Announcements ===
Historically there has been difficulty in relaying the direction of travel a train is headed in a clear message: variations such as "eastbound" and "westbound", and "clockwise" and "anti-clockwise" can be ambiguous. As passengers became more accustomed to digital devices, [[TfL]] considered stopping such announcements and now uses key stations along the route to describe a service (e.g. "via. [[High Street Kensington tube station|High Street Kensington]]").<ref name=":0">{{Cite book|last=Martin|first=Andrew|title=Underground Overground: A passenger's history of the Tube|publisher=Profile Books Ltd.|year=2012|isbn=978-1846684784|location=Pine Street, London}}</ref><ref>{{Cite web|title=London Underground voice announcements|url=https://ilyabirman.net/meanwhile/all/london-underground-voice-announcements/|access-date=2 October 2018|website=ilyabirman.net}}</ref>{{Clear}}

==Rolling stock==
From 1970 to 2014, services were provided using six-car [[C69 stock]] trains, each car having mostly transverse seating and four sets of double doors per side to minimise loading times.<ref name="Hardy">{{cite book|title=London Underground Rolling Stock|last1=Hardy|first1=Brian|date=1997|publisher=Capital Transport|isbn=185414-193-7|edition=14|location=Harrow|pages=44–46}}</ref>

The C69 stock trains were replaced by [[London Underground S7 and S8 Stock|seven-car S Stock]] trains, the first running on the Circle line on 2 September 2013.<ref>{{cite web|url=http://www.globalrailnews.com/2013/09/03/s-stock-trains-take-to-circle-line/|title=S Stock trains take to Circle line|date=3 September 2013|publisher=Global Rail News|access-date=3 September 2013|archive-url=https://web.archive.org/web/20170926042330/https://www.globalrailnews.com/2013/09/03/s-stock-trains-take-to-circle-line/|archive-date=26 September 2017|url-status=dead}}</ref><ref>{{cite magazine |last=Prentice |first=Paul |date=18 September 2013|title=S Stock trains enter service on the Circle and District lines |magazine=Rail |issue=731|page=26}}</ref><ref>{{cite web|url=http://www.tfl.gov.uk/assets/downloads/corporate/Board-20131211-Part-1-Item05-Commissioners-Report-December-2013.pdf|title=Commissioner's Report|author=Hendy, Peter|date=December 2013|publisher=Transport for London|page=5|archive-url=https://web.archive.org/web/20131224110412/http://www.tfl.gov.uk/assets/downloads/corporate/Board-20131211-Part-1-Item05-Commissioners-Report-December-2013.pdf|archive-date=24 December 2013|url-status=dead|access-date=21 December 2013}}</ref> By June 2014 all services were provided by S7 Stock trains. The trains are part of Bombardier's [[Bombardier Movia|Movia]] family,<ref name="Bombardier">{{cite web |title=Metro&nbsp;— London, United Kingdom |publisher=Bombardier |url= http://www.bombardier.com/en/transportation/products-services/rail-vehicles/metros/london--united-kingdom?docID=0901260d8000d19e |access-date=27 January 2011}}</ref> and have a top speed of {{convert|62|mph|abbr=on}}.<ref name="Bombardier" /> A 7-car S Stock train has a capacity of 865 passengers compared to 739 for the 6-car C Stock train it replaced.<ref name="TfL-Cs">{{cite web |url=http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/rollingstock/1616.aspx |title=Rolling Stock: C Stock |access-date=25 November 2012 |publisher=Transport for London |archive-date=5 November 2012 |archive-url=https://web.archive.org/web/20121105134748/http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/rollingstock/1616.aspx |url-status=dead }}</ref><ref name="TfL-SStock">{{cite web|url=http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/rollingstock/21815.aspx|title=Rolling Stock: S stock|publisher=Transport for London|access-date=10 January 2012|archive-date=29 December 2013|archive-url=https://web.archive.org/web/20131229052317/http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/rollingstock/21815.aspx|url-status=dead}} Note: The table erroneously says "Length per car", instead of "Length per train".</ref> With a length of {{convert|117|m}}, the S Stock trains are {{convert|24|m}} longer than the {{convert|93|m|adj=on}} long C stock train, and required station platforms to be lengthened before their introduction.<ref name="MR201012p46ff">{{cite magazine |title='S' stock making its mark |magazine=Modern Railways |location =London |page=46 |date=December 2010}}</ref>

===Depot===
The line's depot is at Hammersmith,{{efn|Position: {{Coord|51|29|52|N|000|13|31|W|region:GB_type:railwaystation|name=30 - Hammersmith Depot}}}} close to Hammersmith station, originally built by the Great Western Railway to be operated by the Metropolitan Railway when the joint Hammersmith & City Railway was electrified in the early 20th century.{{sfn|Jackson|1986|p=185}} Sidings at Barking, Farringdon and near High Street Kensington (known as Triangle Sidings) stable trains overnight.<ref name="linefacts"/>

==Four Lines Modernisation (4LM)==
{{See also|Four Lines Modernisation}}

It was planned that a new signalling system would be used first on the sub-surface lines from the end of 2016,<ref name="MR3">{{cite magazine |last=Abbott|first=James|date=January 2013|title=Sub-surface renewal|pages=38–41 |magazine=Modern Railways }}</ref> but signalling contractor Bombardier was released from its contract by agreement in December 2013 amid heavy criticism of the procurement process<ref>{{Cite magazine |date=3 January 2014|title=London Underground and Bombardier abandon Tube signalling contract|url=https://www.railjournal.com/financial/london-underground-and-bombardier-abandon-tube-signalling-contract/|access-date=2 June 2020 |magazine=International Railway Journal }}</ref> and London Underground subsequently awarded the contract for the project to [[Thales Group|Thales]] in August 2015.<ref>{{Cite magazine |date=13 October 2017|title=London Underground resignalling reaches milestone|url=https://www.railjournal.com/signalling/london-underground-resignalling-reaches-milestone/|access-date=2 June 2020 |magazine=International Railway Journal }}</ref>

With the introduction of S7 Stock, the track, electrical supply, and signalling systems are being upgraded in a programme planned to increase peak-hour capacity on the line by 27 per cent by the end of 2023.<ref name="MR3" /><ref name="TfL-upgrade2">{{cite web|date=February 2011|title=Our Upgrade Plan|url=http://www.tfl.gov.uk/assets/downloads/corporate/our-upgrade-plan-london-underground-february-2011.pdf|url-status=dead|archive-url=https://web.archive.org/web/20120817225410/http://www.tfl.gov.uk/assets/downloads/corporate/our-upgrade-plan-london-underground-february-2011.pdf|archive-date=17 August 2012|access-date=7 December 2012|publisher=Transport for London}}</ref><ref>{{Cite web |title=Four Lines Modernisation|url=https://www.tfl.gov.uk/travel-information/improvements-and-projects/four-lines-modernisation|access-date=2 June 2020|website=Transport for London }}</ref> A single control room for the sub-surface railway opened at Hammersmith on 6 May 2018, and [[Automatic train operation|Communications Based Train Control (CBTC)]] provided by Thales will progressively replace 'fixed block' signalling equipment dating back to the 1940s.<ref name="MR3" /><ref name="MR22">{{cite magazine |last=Stewart|first=Rob|date=January 2013|title=Cityflo 650 to control the SSR|pages=42–43 |magazine=Modern Railways }}</ref>

The rollout of CBTC has been split into sections, each known as a Signal Migration Area (SMA), and are located on the line as follows:<ref>{{Cite magazine |date=October 2020 |magazine=Underground News |publisher=London Underground Railway Society |volume=706|pages=572|title=4LM signalling update}}</ref>

{| class="wikitable sortable"
|+ style="text-align: left;" | Circle line Signal Migration Areas
!data-sort-type="number"|{{Abbr|SMA|Signal Migration Area}}{{efn-lr|SMAs 6–14 concerns parts of the District, Hammersmith & City, and Metropolitan lines.}}
!from
!class="unsortable"|to
!status
!data-sort-type="isoDate"|date
|-
|0.5
|Hammersmith
|Latimer Road
|Completed
|data-sort-value="2019-03" | March 2019
|-
|1
|Latimer Road
|Paddington
|Completed
|data-sort-value="2019-09" | September 2019
|-
|2
|Paddington
|Euston Square
|Completed
|data-sort-value="2019-09" | September 2019
|-
|3
|Euston Square
|Monument
|Completed
|data-sort-value="2021-03" | March 2021
|-
|4
|Monument
|Sloane Square
|Completed
|data-sort-value="2021-04" | April 2021
|-
|5
|Sloane Square
|Paddington
|Completed
|data-sort-value="2022-03" | March 2022
|}
{{notelist-lr}}

==List of stations==
{|class="wikitable sortable"
|-
! Station !! Image !! width=100pt|Opened{{sfn|Rose|2007}} !! Additional information !! Position
|-
|[[Hammersmith tube station (Circle and Hammersmith & City lines)|Hammersmith]] {{access icon}} || [[File:Hammersmith tube station (Hammersmith & City Line) in London, spring 2013 (2).JPG|100px|alt=A brown-bricked building with a rectangular, blue sign reading "HAMMERSMITH STATION" in white letters all under a grey sky]] || 13 June 1864 ||Moved to current position 1 December 1868.{{sfn|Rose|2007}} Connects with [[District line|District]] and [[Piccadilly line|Piccadilly]] lines.
|{{Coord|51|29|39|N|000|13|30|W|region:GB_type:railwaystation|name=01 - Hammersmith tube station}}
|-
|[[Goldhawk Road tube station|Goldhawk Road]] || [[File:Goldhawk Road stn east entrance.JPG|100px|alt=An entrance under a railway brick viaduct with a blue sign reading "GOLDHAWK ROAD STATION" in white letters and two women walking in front all under a grey sky]] || 1 April 1914 || || {{Coord|51|30|07|N|000|13|37|W|region:GB_type:railwaystation|name=02 - Goldhawk Road tube station}}
|-
|[[Shepherd's Bush Market tube station|Shepherd's Bush Market]] || [[File:Shepherd's Bush Market stn east entrance.JPG|100px|alt=A railway on a brick viaduct crosses a road on a steel bridge, with an entrance below a blue sign reading "SHEPHERD'S BUSH MARKET STATION" in white letters]] || 13 June 1864 || Moved to current position 1 April 1914.{{sfn|Rose|2007}} Renamed from "Shepherd's Bush" in 2008.<ref>{{cite press release|url=http://www.tfl.gov.uk/static/corporate/media/newscentre/archive/9969.html |title=Modernisation complete as Shepherd's Bush Tube station re-opens |publisher=Transport for London |date=7 October 2008 |access-date=6 February 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120816190728/http://www.tfl.gov.uk/static/corporate/media/newscentre/archive/9969.html |archive-date=16 August 2012 }}</ref> || {{Coord|51|30|21|N|000|13|35|W|region:GB_type:railwaystation|name=03 - Shepherd's Bush Market tube station}}
|-
|[[Wood Lane tube station|Wood Lane]] {{access icon}} || [[File:Wood Lane tube station 8.jpg|100px|alt=A silver metal and glass building with a blue sign with "WOOD LANE STATION" in white letters]] || 1 May 1908 || Open as Wood Lane (Exhibition) 1908–14 and as required from 1920 as Wood Lane (White City). Renamed White City in 1947 and closed in 1959,{{sfn|Rose|2007}} until re-opened as Wood Lane on 12 October 2008.<ref>{{cite press release |url= http://www.tfl.gov.uk/corporate/media/newscentre/archive/10069.aspx |title=New Wood Lane Underground station opens |date=14 October 2008 |publisher=Transport for London |access-date=8 December 2012}}</ref> ||{{Coord|51|30|35|N|000|13|27|W|region:GB_type:railwaystation|name=04 - Wood Lane tube station}}
|-
|[[Latimer Road]] || [[File:Latimer Road tube stn entrance close-up 2012.JPG|100px|alt=A railway on a brick viaduct crosses a road, an entrance in the brickwork below a sign reading "LATIMER ROAD STATION"]] || 16 December 1868 || Closed from 17 January to 1 August 2011 for engineering and refurbishment works.<ref name="Announcement regarding the temporary closure of Latimer Road">{{Cite press release |url= http://www.tfl.gov.uk/corporate/media/newscentre/archive/17944.aspx |title=Latimer Road station to close for three months for engineering works |date=14 January 2011 |publisher =Transport for London}}</ref>||{{Coord|51|30|50|N|000|13|02|W|region:GB_type:railwaystation|name=05 - Latimer Road tube station}}
|-
|[[Ladbroke Grove tube station|Ladbroke Grove]] || [[File:Ladbroke Grove station.jpg|100px|alt=A brick building with an entrance below a sign reading "LADBROKE GROVE STATION". Three people are in a group outside the entrance]] || 13 June 1864 || Opened as Notting Hill, renamed Notting Hill & Ladbroke Grove in 1880, Ladbroke Grove (North Kensington) in 1919, and Ladbroke Grove in 1938.{{sfn|Rose|2007}}||{{Coord|51|31|02|N|000|12|38|W|region:GB_type:railwaystation|name=06 - Ladbroke Grove tube station}}
|-
|[[Westbourne Park tube station|Westbourne Park]] || [[File:Westbourne Park tube station 1.jpg|100px|alt=A dirty, white-bricked building with a rectangular, dark blue sign reading "WESTBOURNE PARK STATION" in white letters all under a blue sky]] || 1 February 1866 ||Moved to current position 1 November 1871,{{sfn|Rose|2007}} and a Great Western Main Line station from 1871 to 1992.{{sfn|Butt|1995|p=244}} ||{{Coord|51|31|16|N|000|12|04|W|region:GB_type:railwaystation|name=07 - Westbourne Park tube station}}
|-
|[[Royal Oak tube station|Royal Oak]] || [[File:Royal Oak tube station Entrance.jpg|100px|alt=A brown-bricked building with a rectangular, dark blue sign reading "ROYAL OAK STATION" in white letters all under a light blue sky]] || 30 October 1871 || Also a Great Western Main Line station after opening{{sfn|Butt|1995|p=200}} until 1934.||{{Coord|51|31|09|N|000|11|17|W|region:GB_type:railwaystation|name=08 - Royal Oak tube station}}
|-
|[[Paddington tube station (Circle and Hammersmith & City lines)|Paddington]] {{access icon}} {{rail-interchange|london|crossrail}} {{rail-interchange|gb|rail|}}|| [[File:Paddington tube stn Hammersmith & City westbound look east.JPG|100px|alt=A platform with several people waiting for a train. A white square sign has a London Underground roundel with "PADDINGTON" in the centre. To the right there is a track with fourth track electrification and on an adjacent track a blue multiple unit train with red doors waits.]] || 10 January 1863 ||Opened as Paddington (Bishop's Road), renamed in 1948.{{sfn|Rose|2007}} <br />Connects with [[Bakerloo]] and [[District line|District]] lines, [[Elizabeth line]] and National rail services from [[London Paddington station|Paddington]] main line station. || {{Coord|51|31|07|N|000|10|46|W|region:GB_type:railwaystation|name=09 - Paddington station (Circle and Hammersmith & City lines)}}
|-
|[[Edgware Road tube station (Circle, District and Hammersmith & City lines)|Edgware Road]] || [[File:EdgwareRdHammersmith.jpg|100px|alt=A tan-coloured building with brown-framed windows and a sign reading "METROPOLITAN EDGWARE ROAD STATION RAILWAY" in brown letters]] || 10 January 1863 || Connects with [[District line|District]] ,anti-clockwise Circle lines and the hammersmith and city line.||{{Coord|51|31|12|N|000|10|04|W|region:GB_type:railwaystation|name=10 - Edgware Road tube station}}
|-
|[[Baker Street tube station|Baker Street]] || [[File:BakerStEntrance.JPG|100px|alt=A street filled with people in front of a light grey building that has variously coloured signs protruding from it stating a variety of different things]] || 10 January 1863 || Connects with [[Bakerloo]], [[Jubilee line|Jubilee]] and [[Metropolitan line|Metropolitan]] lines. ||{{Coord|51|31|19|N|000|09|25|W|region:GB_type:railwaystation|name=11 - Baker Street tube station}}
|-
|[[Great Portland Street tube station|Great Portland Street]] || [[File:Great Portland St Tube Station.jpg|100px|alt=A beige-bricked building with a blue sign reading "GREAT PORTLAND STREET STATION" in white letters all under a blue sky with white clouds]] || 10 January 1863 || Opened as Portland Road, renamed Great Portland Street in 1917. Named Great Portland Street & Regent's Park 1923–33.{{sfn|Rose|2007}}||{{Coord|51|31|26|N|000|08|38|W|region:GB_type:railwaystation|name=12 - Great Portland Street tube station}}
|-
|[[Euston Square tube station|Euston Square]] || [[File:Euston Square stn south entrance.JPG|100px|alt=A building covered in windows with a blue sign reading "EUSTON SQUARE STATION" in white letters all under a blue sky with white clouds]] || 10 January 1863 || Opened as Gower Street and renamed in 1909.{{sfn|Rose|2007}} Street connection with [[Lioness line]] and National rail services from {{rws|Euston}} main line station.||{{Coord|51|31|33|N|000|08|09|W|region:GB_type:railwaystation|name=13 - Euston Square tube station}}
|-
|[[King's Cross St Pancras]] {{access icon}} {{rint|London|thameslink}} {{rail-interchange|gb|rail|}} {{rail-interchange|eurostar|}} || [[File:King's Cross St Pancras tube stn Euston Rd NE entrance.JPG|100px|alt=Beneath a blue sign reading "KING'S CROSS ST. PANCRAS UNDERGROUND STATION several people exit from an entrance leading to steps down. To the right there are silver doors under a sign reading "Lift". The sky is overcast, above the entrance is a dark blue temporary building]] || 10 January 1863 || Opened as King's Cross, renamed King's Cross & St. Pancras in 1925 and King's Cross St. Pancras in 1933. Moved to current position in 1941.{{sfn|Rose|2007}}<br />Connects with [[Northern line|Northern]], [[Piccadilly line|Piccadilly]] and [[Victoria line|Victoria]] lines and National and International Rail Services from [[St Pancras railway station|St Pancras]] and [[London King's Cross railway station|King's Cross]] main line stations.||{{Coord|51|31|49|N|000|07|27|W|region:GB_type:railwaystation|name=14 - King's Cross St Pancras tube station}}
|-
|[[Farringdon station|Farringdon]] {{access icon}} {{rail-interchange|london|crossrail}} {{rint|London|thameslink}} {{rail-interchange|gb|rail|}}|| [[File:Farringdon station building.JPG|100px|alt=A street view of a pale stone two storey building. Across the top of the building signs read "FARRINGDON & HIGH HOLBORN STATION" and "METROPOLITAN RAILWAY" in gold colour lettering. At ground level a canopy extends into the street around a blue sign reads "FARRINGDON STATION" with the London Underground roundel and National Rail symbols, and just above an entrance is a gold lettering reading "ENTRANCE". Either side of the entrance are shops, bicycles are in bicycle stands and people are walking on the pavement in front of the building]] || 10 January 1863 || Interchangeable with National Rail (Thameslink) services and the Elizabeth line. Opened as Farringdon Street, and moved to current position in 1865. Renamed Farringdon & High Holborn in 1922 and Farringdon in 1936.{{sfn|Rose|2007}} ||{{Coord|51|31|12|N|000|06|19|W|region:GB_type:railwaystation|name=15 - Farringdon station}}
|-
|[[Barbican tube station|Barbican]] || [[File:Barbican station entrance.JPG|100px|alt=Across a road with a London taxi and a car is an entrance. This has people standing in it and above is a blue rectangular sign reading "BARBICAN STATION" in white and above this is a bridge linking the building]] || 23 December 1865 || Opened as Aldersgate Street, then Aldersgate in 1910, Aldersgate & Barbican in 1923 and Barbican in 1968.{{sfn|Rose|2007}} ||{{Coord|51|31|13|N|000|05|52|W|region:GB_type:railwaystation|name=16 - Barbican tube station}}
|-
|[[Moorgate station|Moorgate]] {{rail-interchange|london|crossrail}} {{rail-interchange|gb|rail|}}|| [[File:Moorgate entrance Mgate.JPG|100px|alt=Across a street and behind black bollards is a brick building of at least two storeys. The ground floor is stone coloured and two people are standing in a dark entrance beneath a blue rectangular sign reading "MOORGATE STATION" in white. Above this, attached to be wall at 90 degrees is a white rectangular sign with the National Rail logo and London Underground roundel. Above this, below three windows, blue lettering reads "MOORGATE STATION"]] || 23 December 1865 || Opened as Moorgate Street, renamed in 1924.{{sfn|Rose|2007}}<br />Connects with [[Northern line]] and National rail services from the main line [[Northern City Line]]. The Elizabeth line is interchangeable via [[Liverpool Street station]] owing to the long platforms. ||{{Coord|51|31|07|N|000|05|19|W|region:GB_type:railwaystation|name=17 - Moorgate station}}
|-
|[[Liverpool Street station|Liverpool Street]] {{rail-interchange|london|crossrail}} {{rail-interchange|london|overground}} {{rail-interchange|gb|rail|}}|| [[File:Liverpool Street station entrance Bishopsgate.JPG|100px|alt=The end of a brick building with arched windows and sloping roofs lies between two towers with steeples. In front of this is a white metal and glass structure. People are standing and walking in the street in front.]] || 11 July 1875 || From February to July 1875 trains used platforms in the mainline station.{{sfn|Jackson|1986|p=70}}<br />Connects with [[Central line (London Underground)|Central]] and [[Hammersmith & City]] lines and [[Weaver line]], Elizabeth line and National rail services from [[Liverpool Street railway station|Liverpool Street]] mainline station. Elizabeth Line services via [[Stratford station|Stratford]] and [[Shenfield railway station|Shenfield]] from platforms 15, 16 and 17. ||{{Coord|51|31|04|N|000|04|59|W|region:GB_type:railwaystation|name=18 - Liverpool Street station}}
|-
|[[Aldgate tube station|Aldgate]] || [[File:Aldgate-Station-Entrance.jpg|100px|alt=A light grey building with "M.R. ALDGATE STATION M.R." written in stone on the front face and a black car driving in the foreground]] || 18 November 1876 || Connects with [[Metropolitan line]].
|{{Coord|51|30|50|N|000|04|34|W|region:GB_type:railwaystation|name=19 - Aldgate tube station}}
|-
|[[Tower Hill tube station|Tower Hill]] {{access icon}} || [[File:Tower hill entrance.jpg|100px|alt=A grey, many-windowed castle with flags flying from its turrets in the background, several people walking in the foreground, and a bright sky above]] || 25 September 1882 || The Metropolitan Railway opened "Tower of London", however closed this in 1884 as the District Railway had opened "Mark Lane" nearby. This station was renamed "Tower Hill" in 1946 and moved to the site of the "Tower of London" station in 1967.{{sfn|Rose|2007}}{{sfn|Jackson|1986|p=110}} Connects with [[District]] line, [[Docklands Light Railway|DLR]] from [[Tower Gateway]], National rail services from [[Fenchurch Street railway station|Fenchurch Street]] mainline station, and Riverboat services from [[Tower Millennium Pier|Tower Pier]] ||{{Coord|51|30|36|N|000|04|34|W|region:GB_type:railwaystation|name=20 - Tower Hill tube station}}
|-
|[[Bank–Monument station|Monument]] {{rint|london|dlr}} || [[File:Monument station east entrance.JPG|100px|alt=An entrance in a larger building under a sign reading "MONUMENT STATION" reveals banisters leading down. A woman is walking out of the entrance]] || 6 October 1884 || Opened as Eastcheap, renamed The Monument in 1884.{{sfn|Rose|2007}} Escalator connection to [[Bank-Monument station|Bank]] station giving connections with [[Central line (London Underground)|Central]], [[Northern line|Northern]], [[Waterloo & City]] and [[Docklands Light Railway|DLR]].||{{Coord|51|30|47|N|000|05|17|W|region:GB_type:railwaystation|name=21 - Bank–Monument station}}
|-
|[[Cannon Street station#London Underground|Cannon Street]] {{rail-interchange|gb|rail|}}|| [[File:CannonStreet.jpg|100px|alt=A building with four people walking in front of it, one man in a white shirt sitting in front of it, and one white vehicle driving in front of it]] || 6 October 1884 || Connects with [[Cannon Street station|Cannon Street]] main line station.||{{Coord|51|30|37|N|000|05|27|W|region:GB_type:railwaystation|name=22 - Cannon Street station}}
|-
|[[Mansion House tube station|Mansion House]] || [[File:Mansionhouse300.jpg|100px|alt=A beige-bricked building with a rectangular, dark blue sign reading "MANSION HOUSE STATION" in white letters and a yellow sign reading "OFFICES TO LET"]] || 3 July 1871 || ||{{Coord|51|30|44|N|000|05|39|W|region:GB_type:railwaystation|name=23 - Mansion House tube station}}
|-
|[[Blackfriars station|Blackfriars]] {{access icon}} {{rint|London|thameslink}} {{rail-interchange|gb|rail|}}|| [[File:Blackfriars tube stn and Thameslink northern entrance close up 2012.JPG|100px|alt=A glass structure with gray slats on higher floor; an entrance leads under a canopy with a sign reading "BLACKFRIARS STATION" into a large internal space seen through the glass, People are walking into the entrance and coming up steps from an underpass.]] || 30 May 1870 || Connects with National rail services from [[Blackfriars station|Blackfriars]] main line station, including [[Thameslink]] services, and Riverboat services from [[Blackfriars Pier]] ||{{Coord|51|30|42|N|000|06|11|W|region:GB_type:railwaystation|name=24 - Blackfriars station}}
|-.
|[[Temple tube station|Temple]] || [[File:Templetube.jpg|100px|alt=A grey building with a rectangular, white sign on a rounded corner reading "TEMPLE STATION" in black letters all under a blue sky]] || 30 May 1870 || Opened as The Temple.{{sfn|Rose|2007}} ||{{Coord|51|30|40|N|000|06|52|W|region:GB_type:railwaystation|name=25 - Temple tube station}}
|-
|[[Embankment tube station|Embankment]] || [[File:Embankment station.jpg|100px|alt=A grey building with a blue sign reading "EMBANKMENT STATION" in white letters and people standing in the foreground all under a white sky]] || 30 May 1870 || Opened as Charing Cross, renamed Charing Cross Embankment in 1974 and to the current name from 1976.{{sfn|Rose|2007}} Connects with [[Bakerloo]] and [[Northern line|Northern]] lines, National rail services from [[Charing Cross railway station|Charing Cross]] main line station, and Riverboat services from [[Embankment Pier]] || {{Coord|51|30|25|N|000|07|19|W|region:GB_type:railwaystation|name=26 - Embankment tube station}}
|-
|[[Westminster tube station|Westminster]] {{access icon}} || [[File:Westminster station entrance Portcullis House.JPG|100px|alt=A large crowd of people walking on a grey sidewalk next to a black road where two vehicles are driving from the left to the right]] || 24 December 1868 || Opened as Westminster Bridge, renamed in 1907.{{sfn|Rose|2007}} Connects with [[Jubilee line|Jubilee]] line.||{{Coord|51|30|04|N|000|07|30|W|region:GB_type:railwaystation|name=27 - Westminster tube station}}
|-
|[[St James's Park tube station|St James's Park]] || [[File:St James's Park stn entrance Palmer Street.JPG|100px]] || 24 December 1868 ||The former London Underground Headquarters offices, [[55 Broadway]], were built over the station. ||{{Coord|51|29|58|N|000|08|04|W|region:GB_type:railwaystation|name=28 - St James's Park tube station}}
|-
|[[London Victoria station|Victoria]] {{access icon}} {{rail-interchange|gb|rail|}}|| [[File:London Victoria station -14Oct2008.jpg|100px|alt=A grey building with three rectangular, white signs reading "London Victoria Station" in black letters all under a clear, white sky]] || 24 December 1868 || Connects with [[Victoria line|Victoria]] line, National rail services from [[London Victoria station|Victoria]] main line station and Victoria bus station.||{{Coord|51|29|48|N|000|08|41|W|region:GB_type:railwaystation|name=29 - London Victoria station}}
|-
|[[Sloane Square tube station|Sloane Square]] || [[File:Sloane Square stn entrance.JPG|100px|alt=A modern looking building with marble coloured tiled wall at ground level with grey cladding above. A small concrete canopy is over the larger of two entrances with blue signs reading "SLOANE SQUARE STATION", people are entering and exiting through the larger entrance.]] || 24 December 1868 || ||{{Coord|51|29|33|N|000|09|24|W|region:GB_type:railwaystation|name=30 - Sloane Square tube station}}
|-
|[[South Kensington tube station|South Kensington]] || [[File:South Kensington station.jpg|100px|alt=A entrance behind a raised bed of green plant and under a blue sign reading "SOUTH KENSINGTON STATION" leads into an arcade of shops. Above the entrance there is a glass panel with white lettering reading "METROPOLITAN AND DISTRICT RAILWAYS" and "SOUTH KENSINGTON STATION".]] || 24 December 1868 || Connects with [[Piccadilly line|Piccadilly]] line.||{{Coord|51|29|39|N|000|10|26|W|region:GB_type:railwaystation|name=31 - South Kensington tube station}}
|-
|[[Gloucester Road tube station|Gloucester Road]] || [[File:GloucesterRoadTube.jpg|100px|alt=A beige-bricked building with a green sign reading "METROPOLITAN & DISTRICT RAILWAYS GLOUCESTER ROAD STATION" in white letters]] || 1 October 1868 || Opened as Brompton (Gloucester Road), renamed in 1907.{{sfn|Rose|2007}} Connects with [[Piccadilly line|Piccadilly]] and [[District line|District]] lines.||{{Coord|51|29|41|N|000|10|59|W|region:GB_type:railwaystation|name=32 - Gloucester Road tube station}}
|-
|[[High Street Kensington tube station|High Street Kensington]] || [[File:High Street Kensington station October 2013.jpg|100px|alt=A white many-windowed building]] || 1 October 1868 || Opened as Kensington (High Street) and name gradually changed by 1880.{{sfn|Rose|2007}} Connects with [[District line|District]] line Edgware Road branch.||{{Coord|51|30|03|N|000|11|33|W|region:GB_type:railwaystation|name=33 - High Street Kensington tube station}}
|-
|[[Notting Hill Gate tube station|Notting Hill Gate]] || [[File:Notting Hill Gate Tube Station.jpg|100px|alt=A railway station with side platforms either side of two tracks that disappear into darkness under a painted steel bridge like structure topped with a brick wall, covered by a partially glazed barrel roof.]] || 1 October 1868 || Connects with [[Central line (London Underground)|Central]] line.||{{Coord|51|30|32|N|000|11|49|W|region:GB_type:railwaystation|name=34 - Notting Hill Gate tube station}}
|-
|[[Bayswater tube station|Bayswater]] || [[File:Bayswater Station Exterior.jpg|100px|alt=A single storey pale brick building topped with stone railing. Above an entrance is a canopy, around which are rectanglar blue signs reading "BAYSWATER" and "BAYSWATER STATION". People are walking in the street.]] || 1 October 1868 || Opened as Bayswater, renamed Bayswater (Queen's Road) & Westbourne Grove in 1923, Bayswater (Queen's Road) in 1933 and Bayswater (Queensway) in 1946, after which the suffix was gradually dropped.{{sfn|Rose|2007}} ||{{Coord|51|30|43|N|000|11|17|W|region:GB_type:railwaystation|name=35 - Bayswater tube station}}
|-
|[[Paddington tube station (Bakerloo, Circle and District lines)|Paddington]] {{rail-interchange|london|crossrail}} {{rail-interchange|gb|rail|}}|| [[File:Paddington subsurface station building.jpg|100px|alt=A pale two storey stone building, with gold coloured letters at the top reading "METROPOLITAN RAILWAY" and "PADDINGTON STATION", windows on the first floor. On the ground floor there are shops either side of an entrance with a canopy with rectanglar blue signs reading "PADDINGTON STATION". There are cars and a small truck in the road and people are walking on the pavement.]] || 1 October 1868 ||Opened as Paddington (Praed Street), renamed in 1948.{{sfn|Rose|2007}} Connects with [[Bakerloo]] and [[Hammersmith & City]] lines, Elizabeth line and National rail services from [[London Paddington station|Paddington]] main line station. ||
{{Coord|51|30|56|N|000|10|32|W|region:GB_type:railwaystation|name=36 - Paddington station (District line platforms)}}
|}

''The line then continues to Edgware Road where trains terminate, then reverse to traverse the loop in an anticlockwise direction to Hammersmith.''

== Urban myths ==
Owing to its historically circular nature, the line has generated many [[urban myths]] over the years, including a dead man travelling around undiscovered, a school or office using the service to save infrastructure costs and, as an [[April fool]] in the ''[[The Independent|Independent]]'', a new [[particle accelerator]] to coexist alongside passenger services.<ref name=":0" /><ref>{{Cite news |date=1 April 2010 |url= https://www.independent.co.uk/news/science/hadron-collider-ii-planned-for-circle-line-1932744.html |title=Hadron Collider II planned for Circle Line |work=The Independent |location= London |access-date=2 October 2018}}</ref><ref>{{Cite news |url=https://www.independent.co.uk/news/media/press/april-1st-so-were-you-fooled-1934063.html |title=April 1st: So, were you fooled...? |work=The Independent |location=London |date=2 April 2010 |access-date=2 October 2018 }}</ref>

==See also==
{{Portal|London transport}}
* [[Cromwell Curve]]
* [[Toei Oedo Line|Tokyo Toei Oedo Line]] and [[U3 (Hamburg U-Bahn)|Hamburg U3]], two underground lines with similar arrangements

==Notes and references==

===Notes===
{{notelist}}

===References===
{{Reflist|colwidth=30em}}

===Bibliography===
{{refbegin}}
* {{cite book | last=Butt|first=R. V. J.|year = 1995|edition= 1st| title= The Directory of Railway Stations: details every public and private passenger station, halt, platform and stopping place, past and present| publisher = Patrick Stephens Ltd| isbn = 1-8526-0508-1}}
* {{cite book|last=Bruce|first=J Graeme|year=1983|title=Steam to Silver. A history of London Transport Surface Rolling Stock|publisher=Capital Transport|isbn=0-904711-45-5}}
* {{cite book|last1=Day|first1=John R|last2=Reed|first2=John |title=The Story of London's Underground|year=2010|publisher=Capital Transport|isbn=978-1-85414-341-9}}
* {{cite book|last=Green|first=Oliver|year=1987|title=The London Underground: An illustrated history|publisher=[[Ian Allan Publishing|Ian Allan]]|isbn=0-7110-1720-4}}
* {{cite book|last=Horne|first=Mike|title=The Metropolitan Line|year=2003|publisher=Capital Transport|isbn=1-85414-275-5|url-access=registration|url=https://archive.org/details/metropolitanline00mike}}
* {{cite book|title=London's Metropolitan Railway|last=Jackson|first=Alan|year=1986|publisher=David & Charles|isbn=0-7153-8839-8}}
* {{cite book|title=No Need to Ask!|last1=Leboff|last2=Demuth|first1=David|first2=Tim|year=1999|publisher=Capital Transport|isbn=1-85414-215-1}}
* {{cite book|last=Rose|first=Douglas|title=The London Underground: A Diagrammatic History|edition=8th|date=December 2007|orig-year=1980|publisher=Capital Transport|isbn=978-1-85414-315-0}}
* {{cite book|last=Simpson|first=Bill|title=A History of the Metropolitan Railway. Volume 1: The Circle and Extended Lines to Rickmansworth.|publisher=Lamplight Publications|year=2003|isbn=1-899246-07-X}}
{{refend}}

==Further reading==
* {{cite book|last=Croome|first=Desmond F. |title=Circle Line|date=1 February 2003|publisher=Capital Transport|isbn=978-1-85414-267-2}}
* {{cite book|title=London Railway Map|year=2001|publisher=Quail Maps|isbn=978-1898319-54-2}}
* {{cite book |last=Yonge |first=John |editor-last=Jacobs |editor-first=Gerald |title=5: Southern & TfL |edition=3rd |series=Railway Track Diagrams |date=November 2008 |orig-year=1994 |publisher=Trackmaps |location=Bradford on Avon |isbn=978-0-9549866-4-3}}

== External links ==
{{Commons category}}
* {{Official website}}
{{Attached KML|display=title,inline}}

{{Circle line navbox}}

[[Category:London Underground lines]]
[[Category:Railway lines opened in 1884]]
[[Category:Transport in the City of London]]
[[Category:Transport in the City of Westminster]]
[[Category:Transport in the Royal Borough of Kensington and Chelsea]]
[[Category:Transport in the London Borough of Camden]]
[[Category:Transport in the London Borough of Islington]]
[[Category:Transport in the London Borough of Tower Hamlets]]
[[Category:Railway loop lines]]
[[Category:Standard gauge railways in London]]
[[Category:1884 establishments in England]]
[[Category:Circle line (London Underground)| ]]
[[Category:Automatic London Underground lines]]