Editing M25 motorway (section)

==History==

===Plans===
[[File:Ringways 3 & 4.png|thumb|left|Map of Ringways 3 & 4 showing sections combined to form the M25]]

The idea of a general bypass around London was first proposed early in the 20th century. An outer orbital route around the capital had been suggested in 1913, and was re-examined as a motorway route in [[Charles Bressey|Sir Charles Bressey's]] and [[Edwin Lutyens|Sir Edwin Lutyens']] ''The Highway Development Survey, 1937''.{{sfn|Bramley|1946|p=146}} [[Patrick Abercrombie|Sir Patrick Abercrombie's]] ''[[County of London Plan|County of London Plan, 1943]]'' and ''Greater London Plan, 1944'' proposed a series of five roads encircling the capital.{{sfn|Smith|2001|p=148}}<ref>{{cite book|url=https://books.google.com/books?id=sWw9AAAAMAAJ&q=%22county+of+london+plan%22+1943+orbital|title=County of London plan|publisher=London County Council|author=John Henry Forshaw, Sir Patrick Abercrombie|year=1943|page=13}}</ref> The northern sections of the M25 follow a similar route to the [[Outer London Defence Ring]], a concentric series of anti-tank defences and pillboxes designed to slow down a potential German invasion of the capital during [[World War II]].{{sfn|Hamilton|2015|p=19}} This was marked as the D Ring on Abercombie's plans. Following the war, 11 separate [[county council]]s told the [[Ministry of Transport (United Kingdom)|Ministry of Transport]] that an orbital route was "first priority" for London.{{sfn|Asher|2018|p=113}}

Plans stalled because the route was planned to pass through several urban areas, which attracted criticism. The original D Ring through northwest London was intended to be a simple upgrade of streets. In 1951, Middlesex County Council planned a route for the orbital road through the county, passing through [[Eastcote]] and west of [[Bushey]], connecting with the proposed [[M1 motorway]], but it was rejected by the Ministry two years later. An alternative route via [[London Borough of Harrow|Harrow]] and [[Ealing]] was proposed, but this was abandoned after the council revealed the extent of property demolition required.{{sfn|Asher|2018|p=113}}

In 1964, the [[London County Council]] announced the [[London Ringways]] plan, to consist of four concentric motorway rings around London.{{sfn|Asher|2018|p=43,112}} The following year, the transport minister [[Barbara Castle]] announced that the D Ring would be essential to build. The component parts of what became the M25 came from [[London Ringways#Ringway 3|Ringway 3]] / [[M16 motorway]] in the north and [[London Ringways#Ringway 4|Ringway 4]] in the south.{{sfn|Asher|2018|p=113}}

The Ringways plan was controversial owing to the destruction required for the inner two ring roads, ([[London Ringways#Ringway 1|Ringway 1]] and [[London Ringways#Ringway 2|Ringway 2]]). Parts of Ringway 1 were constructed (including the [[West Cross Route]]), despite stiff opposition, before the overall plan was postponed in February 1972. In April 1973, the [[Greater London Council]] elections resulted in a [[Labour Party (UK)|Labour Party]] victory; the party then formally announced the cancellation of the Ringways running inside Greater London.{{sfn|Asher|2018|p=103}} This did not affect the routes that would become the M25, because they were planned as central government projects from the outset.{{sfn|Asher|2018|p=111}}

===Construction===
[[File:M25 - Work In Progress at Tatling End - geograph.org.uk - 37213.jpg|thumb|View north from Higher [[Denham, Buckinghamshire|Denham]] Fire Station at Tatling End on the A40 in July 1984, with the [[Chiltern Main Line]] five-arch 1906 [[Chalfont Viaduct]], originally built to straddle the [[River Misbourne]] ]]
There was no individual [[public inquiry]] into the M25 as a whole.{{sfn|Asher|2018|p=116}} Each section was presented to planning authorities in its own right and was individually justified, with 39 separate public inquiries relating to sections of the route. The need for the ministry to negotiate with local councils meant that more junctions with local traffic were built than originally proposed.{{sfn|Asher|2018|p=117}} A report in 1981 showed that the M25 had the potential to attract office and retail development along its route, negating the proposed traffic improvements and making Central London a less desirable place to work.{{sfn|Asher|2018|p=118}} None of the motorway was prevented from being built by objections at the public inquiries.{{sfn|Hamilton|2015|p=11}} However, as a consequence of the backlash against the Ringways, and criticism at the public inquiries, the motorway was built with environmental concerns in mind. New features included additional earth mounds, cuttings and fences that reduced noise, and over two million trees and shrubs to hide the view of the road.{{sfn|Moran|2009|pp=208–209}}

[[File:Progress on M25 motorway, south of Cobham - geograph.org.uk - 6442228.jpg|thumb|right|South of Cobham in October 1983]]
Construction of parts of the two outer ring roads, Ringways 3 and 4, began in 1973. The first section, between South Mimms and Potters Bar in Hertfordshire (junctions 23 to 24) opened in September 1975.{{sfn|Asher|2018|p=115}}<ref name="tmad">{{cite web|title=M25 : London Orbital Motorway – Dates|url=http://www.ukmotorwayarchive.org.uk/en/motorways/motorway-listing/m25-london-orbital-motorway/dates.cfm|archive-url=https://web.archive.org/web/20200803151154/http://www.ukmotorwayarchive.org.uk/en/motorways/motorway-listing/m25-london-orbital-motorway/dates.cfm|archive-date=3 August 2020|work=UK Motorway Archive}}</ref> It was provisionally known as the M16 and was given the temporary general-purpose road designation [[A1178 road|A1178]].<ref>{{cite news|url=https://www.independent.co.uk/travel/news-and-advice/simon-calder-how-london-got-its-ring-road-2088171.html|title=How London got its Ring Road|first=Simon|last=Calder|newspaper=The Independent|date=25 September 2010|access-date=11 May 2019}}</ref> A section of the North Orbital Road between [[Rickmansworth]] and [[Hunton Bridge]] was proposed in 1966, with detailed planning in 1971. The North Orbital Extension was given the go-ahead in January 1973, from Maple Cross. It was 6.2 miles, and was to cost £6.5m.<ref>''Buckinghamshire Examiner'' Friday 26 January 1973, page 1</ref> The road was constructed to motorway standards and opened on Thursday 26 February 1976, as a section of the [[A405 road|A405]].<ref>''Birmingham Daily Post'' Thursday 26 February 1976, page 25</ref><ref>{{London Gazette | issue = 47053 | date = 28 October 1976 | pages = 14527-14528}}</ref> It eventually became part of the M25's route.{{sfn|Asher|2018|p=115}}<ref name=tmad/> The section to the south, from [[Heathrow Airport]] to Rickmansworth had five separate routes proposed when a public inquiry was launched in 1974. The Department of Transport sent out 15,000 questionnaires about the preferred route, with 5,000 replies. A route was fixed in 1978, with objections delaying the start of construction in 1982.{{sfn|Hamilton|2015|p=11}}

[[File:Progress on M25 motorway, south of Cobham - geograph.org.uk - 6442227.jpg|thumb|right|Construction in October 1983]]
The southern section of what became the M25 through Surrey and Kent was first conceived to be an east–west road south of London to relieve the [[A25 road|A25]], and running parallel to it, with its eastern end following the route of what is now the [[M26 motorway|M26]]. It was originally proposed as an all-purpose route, but was upgraded to motorway standard in 1966. It was the first section of the route announced as M25 from the beginning. The first section from [[Godstone]] to [[Reigate]] (junctions 6 to 8) was first planned in 1966 and opened in February 1976.{{sfn|Asher|2018|p=115}}<ref name=tmad/> A section of Ringway 3 south of the river between Dartford and Swanley (junctions 1 to 3) was constructed between May 1974 and April 1977.<ref name=tmad/>

[[File:Bell Common Tunnel - geograph.org.uk - 53233.jpg|thumb|left|Inside the [[bell Common#Tunnel|Bell Common Tunnel]] near [[Epping, Essex|Epping]]]]
In 1975, following extensive opposition to some parts of Ringway 3 through Middlesex and South London, the transport minister [[John Gilbert, Baron Gilbert|John Gilbert]] announced that the north section of Ringway 3 already planned would be combined with the southern section of Ringway 4, forming a single orbital motorway to be known as the M25, and the M16 designation was dropped. This scheme required two additional sections to join what were two different schemes, from Swanley to Sevenoaks in the south-east and Hunton Bridge to Potters Bar in the north-west. The section of Ringway 3 west of South Mimms anti-clockwise around London to Swanley in Kent was cancelled.{{sfn|Asher|2018|p=116}}

The section from Potters Bar to the [[Dartford Tunnel]] was constructed in stages from June 1979 onwards, with the final section between [[Waltham Cross]] (junction 25) to [[Theydon Garnon]] (junction 27) opening in January 1984.<ref name=tmad/> This section, running through [[Epping Forest]], attracted opposition and protests. In 1973, local residents had parked [[combine harvester]]s in [[Parliament Square]] in protest against the road, draped with large banners reading "Not Epping Likely". As a consequence of this, the [[Bell Common Tunnel]] that runs in this area is twice as long as originally proposed.{{sfn|Asher|2018|p=119}}

The most controversial section of the M25 was that between Swanley and Sevenoaks (junctions 3 to 5) in Kent across the [[Darenth|Darenth Valley]], [[Badgers Mount]] and the [[North Downs]]. An 1,800-member group named Defend Darenth Valley and the North Downs Action Group (DANDAG) argued that the link was unnecessary, it would damage an [[Area of Outstanding Natural Beauty]] and it would be primarily used by local traffic as a bypass for the old [[A21 road (England)|A21 road]] between Farnborough and Sevenoaks.{{sfn|Asher|2018|p=121}} After a length inquiry process, chaired by [[George Dobry]] [[Queen's Counsel|QC]], the transport minister [[Kenneth Clarke]] announced the motorway would be built as proposed.{{sfn|Asher|2018|p=120}}

The section from the [[M40 motorway]] to the 1970s North Orbital Road construction (junctions 16 to 17) opened in January 1985.{{sfn|Asher|2018|p=121}} The route under the [[Chalfont Viaduct]] meant the motorway was restricted to a width of three lanes in each direction.<ref>{{cite news|url=https://www.telegraph.co.uk/travel/destinations/europe/united-kingdom/galleries/M25-The-best-of-Britains-most-hated-motorway/m25-summary/ |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/travel/destinations/europe/united-kingdom/galleries/M25-The-best-of-Britains-most-hated-motorway/m25-summary/ |archive-date=12 January 2022 |url-access=subscription |url-status=live|title=M25: The best of Britain's most hated motorway|newspaper=The Daily Telegraph|access-date=11 May 2019}}{{cbignore}}</ref>

The [[Prime Minister of the United Kingdom|Prime Minister]], [[Margaret Thatcher]], officially opened the M25 on 29 October 1986, with a ceremony in the section between junctions 22 to 23 ([[London Colney]] and [[South Mimms]]).<ref name=independent_20161017>{{cite news|url=https://www.independent.co.uk/life-style/motoring/features/the-m25-were-on-the-road-to-nowhere-420365.html|title=The M25 : We're on the road to nowhere|newspaper=The Independent|date=17 October 2006|access-date=11 May 2019}}</ref> To avoid the threat of road protesters, the ceremony was held a quarter of a mile from the nearest bridge.{{sfn|Moran|2009|p=209}} The total estimated cost of the motorway was around £1{{nbsp}}billion. It required {{convert|2|e6tonne|e6ST|abbr=off}} of concrete, {{convert|2.5|e6tonne|e6ST|abbr=off}} of [[Asphalt concrete|asphalt]] and involved the removal of {{convert|49|e6m3|e6cuft|abbr=off}} of spoil. Upon completion, it was the longest orbital motorway in the world at {{convert|117|miles}}.{{sfn|Asher|2018|p=121}}{{efn|name=Berliner_Ring_is_longer}} At the opening ceremony, Thatcher announced that {{convert|98|mi}} had been constructed while the [[Conservative Party (UK)|Conservative Party]] were in office, calling it "a splendid achievement for Britain".{{sfn|Moran|2009|p=209}} A 58-page brochure was published, commemorating the completion of the motorway.{{sfn|Hamilton|2015|p=14}}

===Operational history===
[[File:M4 M25 junction.jpg|thumb|The M4/M25 motorway junction (junction 15), near [[Heathrow Airport]]]]

The M25 was initially popular with the public. In the [[1987 United Kingdom general election|1987 general election]], the [[Conservative Party (UK)|Conservatives]] won in every constituency that the motorway passed through, in particular gaining [[Thurrock (UK Parliament constituency)|Thurrock]] from [[Labour Party (UK)|Labour]]. Coach tours were organised for a trip around the new road. However, it quickly became apparent that the M25 suffered from chronic congestion. A report in ''[[The Economist]]'' said it "had taken 70 years to plan [the motorway], 12 to build it and just one to find it was inadequate". Thatcher rebuked the negative response, calling it "carping and criticism".{{sfn|Asher|2018|p=122}}

Traffic levels quickly exceeded the maximum design capacity. Two months before it opened, the government admitted that the three-lane section between junctions 11 and 13 was inadequate and that it would have to be widened to four.{{sfn|Asher|2018|p=122}} In 1990, the [[Secretary of State for Transport]] announced plans to widen the whole of the M25 to four lanes.<ref>{{Cite web|url=https://api.parliament.uk/historic-hansard/written-answers/1990/dec/03/m25|title=M25 (Hansard, 3 December 1990)|website=UK Parliament|date=3 December 1990|access-date=19 July 2019}}</ref> By 1993 the motorway, designed for a maximum of 88,000 vehicles per day, was carrying 200,000.<ref>{{Cite news|url=https://www.independent.co.uk/news/uk/the-bluffers-briefing-on-the-m25-1499570.html|title=The bluffer's briefing on: The M25 | work=The Independent | location=London | date=24 March 1993 | access-date=12 May 2010}}</ref> At that time, the M25 carried 15% of UK motorway traffic and there were plans to add six lanes to the section from junctions 12 to 15, as well as widening the rest of the motorway to four lanes.<ref>{{Cite web|url=https://api.parliament.uk/historic-hansard/commons/1993/feb/18/m25-widening|title=M25 (Widening)|work=[[Hansard|Parliamentary Debates (Hansard)]]|date=18 February 1993|access-date=19 July 2019}}</ref>

In parts, particularly the western third, that plan went ahead. Again, however, plans to widen further sections to eight lanes (four each way) were scaled back in 2009 in response to rising costs. The plans were reinstated in the agreed [[Highways Agency]] 2013–14 business plan.<ref>{{Cite news|url=http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article6571879.ece|archive-url=https://web.archive.org/web/20090709142710/http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article6571879.ece|url-status=dead|archive-date=9 July 2009|title=Rising costs put the brakes on dozens of roadbuilding projects | newspaper=The Times | location=London | first=Ben | last=Webster | date=25 June 2009 | access-date=12 May 2010}}</ref>

In June 1992, the [[Department for Transport]] (DfT) announced a proposal to widen the section close to Heathrow Airport to fourteen lanes by way of three additional link roads.{{sfn|Asher|2018|p=126}} That attracted fierce opposition from [[Road protest in the United Kingdom|anti-motorway protesters]] who were critical of the [[Newbury Bypass]] and other schemes,<ref>{{Cite news|url=https://www.independent.co.uk/news/uk/the-roadblock-that-became-a-bandwagon-1614137.html|title=The roadblock that became a bandwagon|work=The Independent | location=London | first=Christian | last=Wolmar | date=4 April 1995 | access-date=12 May 2010}}</ref> but also from local authorities. Surrey County Council led a formal objection to the widening scheme,{{sfn|Asher|2018|p=126}} and it was cancelled shortly afterwards.<ref>{{Cite news|url=https://www.independent.co.uk/opinion/pointless-lies-that-reveal-so-much-1613955.html|title=Pointless lies that reveal so much |newspaper=The Independent | location=London | first=Nick | last=Cohen | date=2 April 1995 | access-date=12 May 2010}}</ref> In 1994, the Standing Advisory Committee on Trunk Road Appraisal published a report saying that "the M25 experience most probably does ... serve as an example of a case where roads generate traffic" and that further improvements to the motorway were counter-productive.{{sfn|Asher|2018|p=126}} In April 1995, the Transport Minister [[Brian Mawhinney]] announced that the Heathrow link roads would be scrapped.{{sfn|Asher|2018|p=127}}

[[File:M25 motorway 2004-04-25.jpg|thumb|left|The M25 motorway near Heathrow, showing a [[Motorway Incident Detection and Automatic Signalling|MIDAS]] installed gantry]]

In 1995, a contract was awarded to widen the section between junctions 8 and 10 from six to eight lanes at a cost of £93.4{{nbsp}}million,<ref>{{Cite news|url=http://www.cnplus.co.uk/news/m25-scoop-for-balfour-in-surrey/955396.article|title=M25 scoop for Balfour in Surrey|publisher=Construction News|access-date=12 May 2019}}</ref> and a [[Motorway Incident Detection and Automatic Signalling]] (MIDAS) system was introduced from junction 10 to junction 15 in 1995, at a cost of £13.5M. That was extended to junction 16 in 2002, at a cost of £11.7M. The system consists of a distributed network of traffic and weather sensors, [[speed camera]]s and [[Speed limit#Variable speed limits|variable-speed signs]], that control traffic speeds with little human supervision. It has improved traffic flow slightly, reducing the amount of start-stop driving.<ref>{{Cite web|url=http://www.dft.gov.uk/itstoolkit/CaseStudies/m25-controlled-motorway.htm|title=Case Study – M25 Controlled Motorway|work=Highways Agency|url-status=dead|archive-url=https://web.archive.org/web/20120926095159/http://www.dft.gov.uk/itstoolkit/CaseStudies/m25-controlled-motorway.htm |archive-date=26 September 2012}}</ref>

After Labour won the [[1997 United Kingdom general election|1997 election]], the road budget was cut from £6{{nbsp}}billion to £1.4{{nbsp}}billion.{{sfn|Asher|2018|p=127}} However, the DfT announced new proposals to widen the section between junction 12 (M3) and junction 15 (M4) to 12 lanes. At the [[Heathrow Terminal 5]] public inquiry, a Highways Agency official said that the widening was needed to accommodate traffic to the proposed new terminal, but the transport minister said that no such evidence had been given.<ref>{{Cite news|url=https://www.independent.co.uk/news/minister-gives-green-light-to-widen-m25-1274054.html|title=Minister gives green light to widen M25|work=The Independent | location=London | first=Christian | last=Wolmar | date=21 March 1997 | access-date=12 May 2010}}</ref> Environmental groups objected to the decision to go ahead with a scheme to create the widest motorways in the UK, without holding a [[public inquiry]].<ref>{{Cite web|url=http://www.getsurrey.co.uk/news/s/80175_plans_to_widen_m25_to_12_lanes_under_attack |title=Plans to widen M25 to 12 lanes under attack | work = Get Surrey | url-status=dead |archive-url=https://web.archive.org/web/20130614224728/http://www.getsurrey.co.uk/news/s/80175_plans_to_widen_m25_to_12_lanes_under_attack |archive-date=14 June 2013 |access-date=12 August 2020}}</ref> [[Friends of the Earth]] claimed the real reason for the widening was to support Terminal 5.{{sfn|Asher|2018|p=127}} The decision was again deferred. A ten-lane scheme was announced in 1998,<ref>{{Cite magazine|url=https://www.newcivilengineer.com/archive/baa-makes-plans-for-terminal-5-despite-inquiry-06-08-1998/|title=BAA makes plans for Terminal 5 despite inquiry|magazine=New Civil Engineer|date=6 August 1998}}</ref> and the £148{{nbsp}}million 'M25 Jct 12 to 15 Widening' contract was awarded to [[Balfour Beatty]] in 2003.<ref>{{cite web|url=http://www.bbcel.co.uk/capabilities/roads/62_m25-junctions-12-15-widening |title=M25 Junctions 12 – 15 Widening |quote=In 2003, Balfour Beatty Civil Engineering was awarded the £148 million contract to widen the 10-mile stretch of the M25, between Junction 12 (the M3 Interchange) and Junction 15 (the M4 Interchange). |url-status=dead |archive-url=https://web.archive.org/web/20120317091615/http://www.bbcel.co.uk/capabilities/roads/62_m25-junctions-12-15-widening |archive-date= 17 March 2012 }}</ref> The scheme was completed in 2005, with dual-five lanes between junctions 12 and 14 and dual-six lanes from junctions 14 to 15.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/4084.aspx|title=M25 Jct 12 to 15 Widening|work=Highways Agency|archive-url=http://webarchive.nationalarchives.gov.uk/20080926001640/http://www.highways.gov.uk/roads/projects/4084.aspx|archive-date=26 September 2008}}</ref>

In 2007, junction 25 (A10/Waltham Cross) was remodelled to increase capacity. The nearby Holmesdale Tunnel was widened to three lanes in an easterly direction, and an additional left-turn lane added from the A10 onto the motorway. The total cost was £75{{nbsp}}million.<ref>{{Cite web|url=http://www.highways.gov.uk/news/pressrelease.aspx?pressreleaseid=132377|title=£75 Million Refurbishment for M25 Holmesdale Tunnel and Junction 25 Improvement work starts on Saturday 6 May |work=Highways Agency |archive-url=http://webarchive.nationalarchives.gov.uk/20081106072611/http://www.highways.gov.uk/news/pressrelease.aspx?pressreleaseid=132377 |archive-date=6 November 2008}}</ref><ref>{{cite web|url=https://highwaysengland.citizenspace.com/he/m25-junction-25-improvement-scheme/ |title=M25 Junction 25 Improvement |work=Highways England |access-date=13 May 2019}}</ref>

Work to widen the exit slip-roads in both directions at junction 28 ([[A12 road (England)|A12]] / A1023) was completed in 2008. That was designed to reduce the amount of traffic queuing on the slip roads at busy periods, particularly traffic from the clockwise M25 joining the northbound A12.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/3520.aspx|title=M25 Junction 28 / A12 / Brook Street Interchange|work=Highways Agency|archive-url=http://webarchive.nationalarchives.gov.uk/20080926001943/http://www.highways.gov.uk/roads/projects/3520.aspx|archive-date=26 September 2008}}</ref> In 2018, a new scheme was proposed, because the junction had reached capacity, accommodating over 7,500 vehicles per hour. The scheme involved building a two-lane link road between the M25 and the A12. The work was expected to be completed around 2021/22.<ref>{{cite news|url=https://www.eadt.co.uk/business/final-consultation-on-scheme-for-a12-m25-brentwood-junction-1-5806376|title=A12 junction to get major overhaul|newspaper=East Anglian Daily Times|date=5 December 2018|access-date=13 May 2019}}</ref>

===Widening===
[[File:Widening of the M25 Motorway near South Mimms.jpg|thumb|Widening of the M25 Motorway near South Mimms]]

In 2006, the Highways Agency proposed widening {{convert|63|mi|km}} of the M25 from six to eight lanes, between junctions 5 and 6, and 16 to 30, as part of a Design, Build, Finance and Operate (DBFO) project.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/7717.aspx|title=Prequalification Document|work=Highways Agency|access-date=20 January 2008|archive-url=http://webarchive.nationalarchives.gov.uk/20081107095325/http://www.highways.gov.uk/roads/7717.aspx|archive-date=7 November 2008}}</ref> A shortlist of contractors was announced in October 2006 for the project, which was expected to cost £4.5{{nbsp}}billion.<ref>{{Cite web |url=http://www.contractjournal.com/Articles/2006/10/13/52504/highways-agency-announces-shortlist-for-4.5bn-m25-dbfo.html |title=Highways Agency announces shortlist for £4.5bn M25 DBFO |publisher=Contract Journal |access-date=20 January 2008 |archive-date=16 January 2016 |archive-url=https://web.archive.org/web/20160116183257/http://www.contractjournal.com/Articles/2006/10/13/52504/highways-agency-announces-shortlist-for-4.5bn-m25-dbfo.html |url-status=dead }}</ref> Contractors were asked to resubmit their bids in January 2008,<ref>{{Cite web|url=https://www.constructionnews.co.uk/archive/highways-agency-calls-for-m25-widening-bids-to-be-resubmitted-16-01-2008/ |title=Highways Agency calls for M25 widening bids to be resubmitted |publisher=Construction Journal |date=16 January 2008 |author=Andrea Klettner |access-date=20 January 2008 |url-status=live |archive-url=https://web.archive.org/web/20200812103507/https://www.constructionnews.co.uk/archive/highways-agency-calls-for-m25-widening-bids-to-be-resubmitted-16-01-2008/ |archive-date=12 August 2020}}</ref> and in June 2009 the new transport minister indicated that the cost had risen to £5.5{{nbsp}}billion and the benefit to cost ratio had dropped considerably.<ref>{{Cite magazine|url=https://www.newcivilengineer.com/latest/cost-escalation-hits-m25-widening-benefit-to-cost-ratios-16-06-2009/|title=Cost escalation hits M25 widening benefit to cost ratios|magazine=New Civil Engineer|date=16 June 2009}}</ref> In January 2009 the government announced that plans to widen the sections from junctions 5 to 7 and 23 to 27 had been 'scrapped' and that hard shoulder running would be introduced instead. However, widening to four lanes was reinstated in the 2013–14 Highways Agency Business Plan.<ref name=bp>{{cite web|url=http://assets.highways.gov.uk/about-us/corporate-documents-business-plans/S120450_Highways_Agency_Business_Plan_2013-14.pdf |title=Business Plan 2013–14 |url-status=dead|archive-url=https://web.archive.org/web/20130515101239/http://assets.highways.gov.uk/about-us/corporate-documents-business-plans/S120450_Highways_Agency_Business_Plan_2013-14.pdf |archive-date=15 May 2013 |work=Highways Agency}}</ref><ref>{{Cite news|url=https://www.theguardian.com/politics/2009/jan/18/motorways-geoff-hoon|title=Ministers scrap plan to widen motorways | newspaper=The Guardian | location=London | first=Toby | last=Helm | date=18 January 2009 | access-date=12 May 2010}}</ref>

In 2009, a £6.2{{nbsp}}billion M25 DBFO [[private finance initiative]] contract<ref>{{Cite news|url=http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article6322870.ece|archive-url=https://web.archive.org/web/20110612191248/http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article6322870.ece|url-status=dead|archive-date=12 June 2011|title=PFI deal for M25 agreed despite price rise | newspaper=The Times | location=London | first=Ben | last=Webster | date=20 May 2009 | access-date=12 May 2010}}</ref> was awarded to Connect Plus to widen the sections between junctions 16 to 23 and 27 to 30, and maintain the M25 and the Dartford Crossing for a 30-year period.<ref>{{Cite web|url=http://www.highways.gov.uk/news/pressrelease.aspx?pressreleaseid=174136|title=£6.2 billion M25 Design, Build, Finance and Operate (DBFO) contract awarded|work=Highways Agency|archive-url=http://webarchive.nationalarchives.gov.uk/20091115022317/http://www.highways.gov.uk/news/pressrelease.aspx?pressreleaseid=174136|archive-date=15 November 2009}}</ref>

Work to widen the section between junctions 16 (M40) and 23 (A1(M)) to dual four lanes<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/5747.aspx |title=M25 Jct 16 to 23 Widening |work=Highways Agency|url-status=dead |archive-url=https://web.archive.org/web/20120910043422/http://www.highways.gov.uk/roads/projects/5747.aspx |archive-date=10 September 2012 }}</ref> started in July 2009 at an estimated cost of £580{{nbsp}}million.<ref>{{Cite news|url=http://news.bbc.co.uk/1/hi/england/8139940.stm|title=M25 widening to four lanes begins|work=BBC News | date=8 July 2009 | access-date=12 May 2010}}</ref> The junction 16 to 21 (M1) section was completed by July 2011 and the junction 21 to 23 by June 2012.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/13825.aspx|title=Highways Agency Timetable|archive-url=http://webarchive.nationalarchives.gov.uk/20080926033144/http://www.highways.gov.uk/roads/projects/13825.aspx|archive-date=26 September 2008}}</ref> Works to widen the junctions 27 (M11) to 30 (A13) section to dual four lanes also started in July 2009. The junction 27 to 28 (A12) section was completed in July 2010,<ref>{{Cite web|url=http://www.fleetdirectory.co.uk/fleet-news/index.php/2009/09/30/weekly-summary-of-roadworks-in-m25-sphere-30092009/|title=Weekly Summary of Roadworks in M25 Sphere – 30 September 2009|work=Fleet Directory|access-date=11 October 2009|archive-url=https://web.archive.org/web/20091002035548/http://www.fleetdirectory.co.uk/fleet-news/index.php/2009/09/30/weekly-summary-of-roadworks-in-m25-sphere-30092009/|archive-date=2 October 2009|url-status=dead}}</ref> and the junction 28 to 29 (A127) in June 2011, and finally the junction 29 to 30 (A13) section opened in May 2012.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/5739.aspx |title=M25 Jct 27 to 30 Widening |work=Highways Agency |url-status=dead |archive-url=https://web.archive.org/web/20120329130227/http://www.highways.gov.uk/roads/projects/5739.aspx |archive-date= 29 March 2012 }}</ref>

Work to introduce smart motorway technology and permanent [[Shoulder (road)|hard shoulder running]] on two sections of the M25 began in 2013. The first section between junctions 5 (A21/M26) and 7 (M23) started construction in May 2013 with the scheme being completed and opened in April 2014.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/5735.aspx|title=M25 Junctions 5 to 7 Managed Motorways|work=Highway Agency|access-date=11 October 2009|archive-url=https://web.archive.org/web/20120908034609/http://www.highways.gov.uk/roads/projects/5735.aspx|archive-date=8 September 2012|url-status=dead}}</ref> The second section, between junctions 23 (A1/A1(M)) and 27 (M11), began construction in February 2013 and was completed and opened in November 2014.<ref>{{Cite web|url=http://www.highways.gov.uk/roads/projects/5743.aspx|title=M25 Junctions 23 to 27 Managed Motorways|work=Highways Agency|access-date=10 December 2008|archive-url=https://web.archive.org/web/20120817142908/http://www.highways.gov.uk/roads/projects/5743.aspx|archive-date=17 August 2012|url-status=dead}}</ref>

In December 2016, Highways England completed the capacity project at junction 30 (Thurrock) as part of the [[Thames Gateway]] Delivery Plan.<ref>{{cite web|url=http://roads.highways.gov.uk/projects/m25-junction-30a13-corridor-relieving-congestion-scheme/|archive-url=https://web.archive.org/web/20170910054525/http://roads.highways.gov.uk/projects/m25-junction-30a13-corridor-relieving-congestion-scheme/|url-status=dead|archive-date=10 September 2017|title=M25 Junction 30 A13 corridor relieving congestion scheme|date=10 September 2017|work=Highways England}}</ref> The £100{{nbsp}}million scheme included widening the M25 to four lanes, adding additional link roads, and improvements to drainage.<ref>{{cite web|url=https://www.highwaysindustry.com/m25-junction-officially-open-after-100million-upgrade/|title=M25 junction officially open after £100million upgrade|work=Highways Industry|date=2 December 2016|access-date=12 May 2019}}</ref>

Work began to widen the M25 and A3 around junction 10 in November 2022.<ref>{{cite news| url  = https://www.getsurrey.co.uk/news/surrey-news/m25-a3-wisley-interchange-looks-30194375 |title=M25 and A3 Wisley interchange looks unrecognisable in video showing new bridge works|work=Get Surrey|date=21 October 2024|accessdate=25 October 2024}}</ref><ref>{{cite news|url=https://www.bbc.co.uk/news/uk-england-surrey-65327256 | title = M25: Thousands of trees replanted after widening work | date = 21 April 2023 | work = BBC News|access-date=25 October 2024}}</ref> The project is intended to limit congestion at the junction and allow traffic to proceed more safely.<ref>{{cite web|url=https://nationalhighways.co.uk/our-roads/m25-junction-10-project-profile/|title=M25 junction 10 project profile|date=15 May 2024 |publisher=National Highways|access-date=27 October 2024}}</ref> However, these plans caused concerns about the amount of woodland that would be required.<ref>{{Cite web|last=Fleming|first=Eleanor|date=18 August 2020|title=RHS Wisley's 'last chance' to save 'irreplaceable' trees from M25-A3 scheme | url = https://www.getsurrey.co.uk/news/surrey-news/rhs-wisley-highways-england-plans-18786153|access-date=18 August 2020|website=SurreyLive}}</ref>

In March 2024, National Highways announced the first all-day closure of the M25 in its operational history. The motorway was closed between junctions 10 and 11 from 15–18 March in order to remove a bridleway bridge.<ref>{{cite web|url=https://nationalhighways.co.uk/article/m25-braced-for-first-ever-planned-full-closure-as-drivers-warned-of-long-delays-and-told-to-only-travel-if-necessary/|title=M25 braced for first ever planned full closure as drivers warned of long delays and told to only travel if necessary|work=National Highways|date=5 March 2024|accessdate=6 March 2024}}</ref><ref>{{cite news|url=https://www.bbc.co.uk/news/business-68482948|title=M25 section to close for entire weekend|work=BBC News|date=6 March 2024|accessdate=6 March 2024}}</ref> The road was closed completely for two other occasions that year, with a final two closures scheduled for 2025.<ref>{{cite news|url=https://www.bbc.co.uk/news/articles/c0jq5p7nyn1o|title=No more M25 weekend closures in 2024|work=BBC News|date=18 July 2024|access-date=27 October 2024}}</ref>