Editing M25 motorway (section)

===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>