 | ||||
|---|---|---|---|---|
| London Orbital Motorway | ||||
 M25 motorway A282 Dartford CrossingShow interactive map _map.svg) Shown with the UK motorway network Show UK motorways map | ||||
 Junction 13 looking south | ||||
| Route information | ||||
Part of E15 and E30[1] | ||||
| Maintained by Connect Plus (contracted toNational Highways) | ||||
| Length | 188 km (117 mi) | |||
| Existed | 1975–present | |||
| History | Opened: 1975 Completed: 1986 | |||
| Major junctions | ||||
| Orbital aroundLondon (in conjunction with theA282) | ||||
| Anti-clockwise end | Dartford (Dartford Crossing southern approach) | |||
| Major intersections |   J3 →M20 motorway   J5 →M26 motorway   J7 →M23 motorway   J12 →M3 motorway   J15 →M4 motorway   J16 →M40 motorway   J21 →M1 motorway  .svg) J23 →A1(M) motorway   J27 →M11 motorway | |||
| Clockwise end | Thurrock (Dartford Crossing northern approach) | |||
| Location | ||||
| Country | United Kingdom | |||
| Counties | Kent,Surrey,Berkshire,Greater London,Buckinghamshire,Hertfordshire,Essex | |||
| Primary destinations | London Dartford Crossing Sevenoaks Gatwick Airport Heathrow Airport Watford Stansted Airport Brentwood Chelmsford Ilford Romford | |||
| Road network | ||||
| ||||
TheM25 orLondon Orbital Motorway is a major road encircling most ofGreater London. The 117-mile-long (188 km) motorway is one of the most important roads in the UK and one of the busiest.Margaret Thatcher opened the final section in 1986, making the M25 the longestring road in Europe upon opening.[a] TheDartford Crossing completes the orbital route but is not classed as motorway; it is classed as atrunk road and designated as theA282. In some cases, including notable legal contexts such as theCommunications Act 2003, the M25 is used as ade facto alternative boundary for Greater London.
In the 1944Greater London Plan,Patrick Abercrombie proposed an orbital motorway around London. This evolved into theLondon Ringways project in the early 1960s, and by 1966, planning had started on two projects,Ringway 3 to the north andRingway 4 to the south. By the time the first sections opened in 1975, it was decided the ringways would be combined into a single orbital motorway. The M25 was one of the first motorway projects to consider environmental concerns and almost 40 public inquiries took place. The road was built as planned despite some protests that included the section over theNorth Downs and aroundEpping Forest which required an extension of theBell Common Tunnel.
Although the M25 was popular during construction, it quickly became apparent that there was insufficient traffic capacity. Because of the public inquiries, several junctions merely served local roads where office and retail developments were built, attracting even more traffic onto the M25 than it was designed for. The congestion has led to traffic management schemes that includevariable speed limit andsmart motorway. Since opening, the M25 has been progressively widened, particularly nearHeathrow Airport.
The M25 almost completely encirclesGreater London and passes briefly through it, in the east and west.[2][3] Junctions 1A–5 are inKent, 6–13 are inSurrey, 14 and a small part of 15 are inHillingdon, Greater London, 15–16 are inBuckinghamshire, 17–24 are inHertfordshire, 25 is inEnfield, Greater London and 26–31 are inEssex.[3] Law enforcement on the road is carried out by an integrated group made up of theMetropolitan,Thames Valley,Essex,Kent,Hertfordshire andSurrey police services.[4]Primary destinations signed ahead on the motorway include theDartford Crossing,Sevenoaks,Gatwick Airport,Heathrow Airport,Watford,Stansted Airport andBrentwood.[5]
To the east of London the two ends of the M25 are joined to complete a loop by the non-motorway A282 Dartford Crossing of theRiver Thames betweenThurrock andDartford. The crossing consists of twin two-lane tunnels and the four-laneQE2 (Queen Elizabeth II) bridge,[6][7] with a main span of 450 metres (1,480 ft).[8] Passage across the bridge or through the tunnels is subject to acharge between 6 am and 10 pm, its level depending on the kind of vehicle. The road is not under motorway regulations so that other traffic can cross the Thames east of theWoolwich Ferry;[b] the only crossing further to the east isa passenger ferry betweenGravesend,Kent, andTilbury,Essex.[10]
At junction 5, the clockwise carriageway of the M25 is routed off the main north–southdual carriageway onto the main east–west dual carriageway with the main north–south carriageway becoming theA21. In the opposite direction, to the east of the point where the M25 diverges from the main east–west carriageway, that carriageway becomes theM26 motorway.[11] From here to junction 8, the M25 follows the edge of theNorth Downs close to several historic buildings such asChevening,Titsey Place,Hever Castle andChartwell.[12][13] The interchange with theM23 motorway nearReigate is afour-level stack; one of only a few examples in Britain.[14] Past this, the M25 runs close to theSurrey Hills National Landscape.[12]
To the west, the M25 passes close to the edge of Heathrow Airport, and within sight ofWindsor Castle.[15] North of this, it goes under theChalfont Viaduct railway bridge, completed in 1906, which carries theChiltern Main Line.Red kites can often be seen overhead to the north of this, up to junction 21. The northern section of the M25 passes close toAll Saints Pastoral Centre nearLondon Colney,Waltham Abbey andCopped Hall.[12][13] This section also features twocut-and-cover tunnels, including theBell Common Tunnel.[13] The north-eastern section of the motorway passes close toNorth Ockendon, the only settlement of Greater London situated outside the M25.[16] It then runs close to theRainham Marshes Nature Reserve before reaching the northern end of the Dartford Crossing.[12]
In 2004, following an opinion poll, theLondon Assembly proposed aligning the Greater London boundary with the M25.[c] "Inside the M25" and "outside/beyond the M25" are colloquial, looser alternatives to "Greater London" sometimes used in haulage. TheCommunications Act 2003 explicitly uses the M25 as the boundary in requiring a proportion of television programmes to be made outside the London area; it states a requirement of "a suitable proportion of the programmes made in the United Kingdom" to be made "in the United Kingdom outside the M25 area", defined in Section 362 as "the area the outer boundary of which is represented by the London Orbital Motorway (M25)".[18][19]
Sections of the M25 form part of two long-distanceE-roads, designated by theUnited Nations Economic Commission for Europe. TheE15, which runs fromInverness toAlgeciras,[20] follows the M25 and A282 clockwise from the A1(M) at junction 23 to the M20 at junction 3;[1] while theE30Cork toOmsk route runs from the M4 at junction 15, clockwise to the A12 at junction 28.[1] The United Kingdom is formally part of the E-roads network but, unlike in other countries, these routes are not marked on any road signs.[21]
The M25 was originally built mostly as a dual three-lane motorway.[22] Much of this has since been widened to dual four lanes for almost half, to a dual five-lanes section between junctions 12 and 14 and a dual six-lane section between junctions 14 and 15. Further widening is in progress of minor sections with plans forsmart motorways in many others.[23]
Twomotorway service areas are on the M25, and two others are directly accessible from it. Those on the M25 areClacket Lane between junctions 5 and 6 (in the south-east) andCobham between junctions 9 and 10 (in the south-west). Those directly accessible from it areSouth Mimms off junction 23 (to the north of London) andThurrock off junction 31 (to the east of London).[24][25]
As is common with other motorways, the M25 is equipped with emergency ("SOS") telephones. These connect to twoNational Highways operated control centres atGodstone (for junctions 1 to 15 inclusive) andSouth Mimms (for 16–31). The Dartford Crossing has a dedicated control centre. There is an extensive network ofclosed-circuit television (CCTV) on the motorway so incidents can be easily identified and located. A number of4×4 vehicles patrol the motorway, attempting to keep traffic moving where possible, and assisting the local police. They can act as arolling roadblock when there are obstacles on the road.[4]
When completed, the M25 only hadstreet lighting for 65 miles (105 km) of its 117-mile (188 km) length.[26] Originally,low pressure sodium (SOX) lighting was the most prominent technology used, but this has been gradually replaced with high-pressure sodium (SON) lighting. As of 2015[update] the motorway has more than 10,000 streetlights.[27] The M25 has a number of pollution control valves along its length, which can shut off drainage in the event of a chemical or fuel spill.[27]
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 inSir Charles Bressey's andSir Edwin Lutyens'The Highway Development Survey, 1937.[28]Sir Patrick Abercrombie'sCounty of London Plan, 1943 andGreater London Plan, 1944 proposed a series of five roads encircling the capital.[29][30] The northern sections of the M25 follow a similar route to theOuter London Defence Ring, a concentric series of anti-tank defences and pillboxes designed to slow down a potential German invasion of the capital duringWorld War II.[31] This was marked as the D Ring on Abercombie's plans. Following the war, 11 separatecounty councils told theMinistry of Transport that an orbital route was "first priority" for London.[32]
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 throughEastcote and west ofBushey, connecting with the proposedM1 motorway, but it was rejected by the Ministry two years later. An alternative route viaHarrow andEaling was proposed, but this was abandoned after the council revealed the extent of property demolition required.[32]
In 1964, theLondon County Council announced theLondon Ringways plan, to consist of four concentric motorway rings around London.[33] The following year, the transport ministerBarbara Castle announced that the D Ring would be essential to build. The component parts of what became the M25 came fromRingway 3 /M16 motorway in the north andRingway 4 in the south.[32]
The Ringways plan was controversial owing to the destruction required for the inner two ring roads, (Ringway 1 andRingway 2). Parts of Ringway 1 were constructed (including theWest Cross Route), despite stiff opposition, before the overall plan was postponed in February 1972. In April 1973, theGreater London Council elections resulted in aLabour Party victory; the party then formally announced the cancellation of the Ringways running inside Greater London.[34] This did not affect the routes that would become the M25, because they were planned as central government projects from the outset.[35]
There was no individualpublic inquiry into the M25 as a whole.[36] 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.[37] 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.[38] None of the motorway was prevented from being built by objections at the public inquiries.[39] 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.[40]
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.[41][42] It was provisionally known as the M16 and was given the temporary general-purpose road designationA1178.[43] A section of the North Orbital Road betweenRickmansworth andHunton 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.[44] The road was constructed to motorway standards and opened on Thursday 26 February 1976, as a section of theA405.[45][46] It eventually became part of the M25's route.[41][42] The section to the south, fromHeathrow 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.[39]
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 theA25, and running parallel to it, with its eastern end following the route of what is now theM26. 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 fromGodstone toReigate (junctions 6 to 8) was first planned in 1966 and opened in February 1976.[41][42] 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.[42]
In 1975, following extensive opposition to some parts of Ringway 3 through Middlesex and South London, the transport ministerJohn 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.[36]
The section from Potters Bar to theDartford Tunnel was constructed in stages from June 1979 onwards, with the final section betweenWaltham Cross (junction 25) toTheydon Garnon (junction 27) opening in January 1984.[42] This section, running throughEpping Forest, attracted opposition and protests. In 1973, local residents had parkedcombine harvesters inParliament Square in protest against the road, draped with large banners reading "Not Epping Likely". As a consequence of this, theBell Common Tunnel that runs in this area is twice as long as originally proposed.[47]
The most controversial section of the M25 was that between Swanley and Sevenoaks (junctions 3 to 5) in Kent across theDarenth Valley,Badgers Mount and theNorth 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 anArea of Outstanding Natural Beauty and it would be primarily used by local traffic as a bypass for the oldA21 road between Farnborough and Sevenoaks.[48] After a length inquiry process, chaired byGeorge DobryQC, the transport ministerKenneth Clarke announced the motorway would be built as proposed.[49]
The section from theM40 motorway to the 1970s North Orbital Road construction (junctions 16 to 17) opened in January 1985.[48] The route under theChalfont Viaduct meant the motorway was restricted to a width of three lanes in each direction.[50]
ThePrime Minister,Margaret Thatcher, officially opened the M25 on 29 October 1986, with a ceremony in the section between junctions 22 to 23 (London Colney andSouth Mimms).[16] To avoid the threat of road protesters, the ceremony was held a quarter of a mile from the nearest bridge.[51] The total estimated cost of the motorway was around £1 billion. It required 2 million tonnes (2.2 million short tons) of concrete, 2.5 million tonnes (2.8 million short tons) ofasphalt and involved the removal of 49 million cubic metres (1,700 million cubic feet) of spoil. Upon completion, it was the longest orbital motorway in the world at 117 miles (188 km).[48][a] At the opening ceremony, Thatcher announced that 98 miles (158 km) had been constructed while theConservative Party were in office, calling it "a splendid achievement for Britain".[51] A 58-page brochure was published, commemorating the completion of the motorway.[52]
The M25 was initially popular with the public. In the1987 general election, theConservatives won in every constituency that the motorway passed through, in particular gainingThurrock fromLabour. 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 inThe 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".[53]
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.[53] In 1990, theSecretary of State for Transport announced plans to widen the whole of the M25 to four lanes.[54] By 1993 the motorway, designed for a maximum of 88,000 vehicles per day, was carrying 200,000.[55] 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.[56]
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 agreedHighways Agency 2013–14 business plan.[57]
In June 1992, theDepartment for Transport (DfT) announced a proposal to widen the section close to Heathrow Airport to fourteen lanes by way of three additional link roads.[58] That attracted fierce opposition fromanti-motorway protesters who were critical of theNewbury Bypass and other schemes,[59] but also from local authorities. Surrey County Council led a formal objection to the widening scheme,[58] and it was cancelled shortly afterwards.[60] 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.[58] In April 1995, the Transport MinisterBrian Mawhinney announced that the Heathrow link roads would be scrapped.[61]
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 million,[62] and aMotorway 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 cameras andvariable-speed signs, that control traffic speeds with little human supervision. It has improved traffic flow slightly, reducing the amount of start-stop driving.[63]
After Labour won the1997 election, the road budget was cut from £6 billion to £1.4 billion.[61] However, the DfT announced new proposals to widen the section between junction 12 (M3) and junction 15 (M4) to 12 lanes. At theHeathrow 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.[64] Environmental groups objected to the decision to go ahead with a scheme to create the widest motorways in the UK, without holding apublic inquiry.[65]Friends of the Earth claimed the real reason for the widening was to support Terminal 5.[61] The decision was again deferred. A ten-lane scheme was announced in 1998,[66] and the £148 million 'M25 Jct 12 to 15 Widening' contract was awarded toBalfour Beatty in 2003.[67] The scheme was completed in 2005, with dual-five lanes between junctions 12 and 14 and dual-six lanes from junctions 14 to 15.[68]
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 million.[69][70]
Work to widen the exit slip-roads in both directions at junction 28 (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.[71] 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.[72]
In 2006, the Highways Agency proposed widening 63 miles (101 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.[73] A shortlist of contractors was announced in October 2006 for the project, which was expected to cost £4.5 billion.[74] Contractors were asked to resubmit their bids in January 2008,[75] and in June 2009 the new transport minister indicated that the cost had risen to £5.5 billion and the benefit to cost ratio had dropped considerably.[76] 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.[23][77]
In 2009, a £6.2 billion M25 DBFOprivate finance initiative contract[78] 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.[79]
Work to widen the section between junctions 16 (M40) and 23 (A1(M)) to dual four lanes[80] started in July 2009 at an estimated cost of £580 million.[81] The junction 16 to 21 (M1) section was completed by July 2011 and the junction 21 to 23 by June 2012.[82] 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,[83] and the junction 28 to 29 (A127) in June 2011, and finally the junction 29 to 30 (A13) section opened in May 2012.[84]
Work to introduce smart motorway technology and permanenthard 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.[85] 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.[86]
In December 2016, Highways England completed the capacity project at junction 30 (Thurrock) as part of theThames Gateway Delivery Plan.[87] The £100 million scheme included widening the M25 to four lanes, adding additional link roads, and improvements to drainage.[88]
Work began to widen the M25 and A3 around junction 10 in November 2022.[89][90] The project is intended to limit congestion at the junction and allow traffic to proceed more safely.[91] However, these plans caused concerns about the amount of woodland that would be required.[92]
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.[93][94] The road was closed completely for two other occasions that year, with a final two closures scheduled for 2025.[95]
The M25 is one of Europe's busiest motorways. In 2003, a maximum of 196,000 vehicles a day were recorded just south of Heathrow, between junctions 13 and 14.[96] The stretch between the nearby junctions 14 and 15 consistently records the highest daily traffic counts on the British strategic road network, with the average flow in 2018 being 219,492 vehicles (lower than the record peak measured in 2014 of 262,842).[97]
Traffic on the M25 is monitored by Connect Plus Services on behalf of National Highways. The company operates a series of transportable CCTV cameras that can be easily moved into congestion hotspots, allowing operators to have a clear view of the motorway and so assess what might be done to tackle particular areas of congestion.[98] Prior to its liquidation in 2018,Carillion was subcontracted to manage traffic on the M25, delivering live alerts from body-worn cameras via 3G, 4G and Wi-Fi.[99]
Since 1995, sections of the M25 have been equipped with variable speed limits, which slow traffic in the event of congestion or an obstruction, and help manage the traffic flow.[100] The scheme was originally trialled between junctions 10 and 16, and was made a permanent fixture in 1997.[101]
The Dartford Crossing is the only fixed vehicle crossing of the Thames east of Greater London.[102] It is also the busiest crossing in the United Kingdom, and consequently puts pressure on M25 traffic.[103] Users of the crossing do not pay a toll, but rather a congestion charge. The signs at the crossing are the same as those deployed over theLondon congestion charge zone.[104]
In 2009, the Department for Transport published options for a newLower Thames Crossing to add capacity to the Dartford Crossing, or create a new road and crossing linking to the M2 and M20 motorways.[105] Plans for that stalled, and were cancelled in 2013 by the Mayor of London,Boris Johnson, being replaced by a proposedGallions Reach Crossing. Initially seen as a straight ferry replacement for theWoolwich Ferry, it was later mooted as a bridge or tunnel.[106][107] By 2019, the plans had changed, with theDocklands Light Railway to be extended toThamesmead instead.[108]
On 11 December 1984, nine people died and ten were injured in a multiple-vehicle collision between junctions 5 and 6. Twenty-six vehicles were involved when dense fog descended suddenly.[109]
On 16 December 1988, several vehicles were stolen and used as getaway for acts of murder and robbery, using the M25 to quickly move between targets. TheM25 Three, includingRaphael Rowe, were tried and sentenced to life imprisonment in 1990. Their convictions were overturned in 2000 and Rowe, who studied journalism while in prison, became aninvestigative journalist for the BBC.[110][111][112]
In 1996,Kenneth Noye murdered Stephen Cameron in aroad rage incident while stopped at traffic lights on an M25 junction in Kent. He was convicted in 2000 and sentenced to life imprisonment.[113] He was released in June 2019.[114][115]
In November 2014, during overnight roadworks, a 16-foot (4.9 m) piece of road surface near junction 9 atLeatherhead failed to set correctly due to rain. This created a 1-foot (0.30 m) pothole in the road and caused a 12-mile (19 km) tailback. The Minister for TransportJohn Hayes criticised the work and the resulting traffic problems.[116]
The M25 has had problems with animals and birds on the carriageway. In 2009, the Highways Agency reported that they had been called out several times a week to remove a swan from the motorway around junction 13.[117] There have been several crashes resulting in horses escaping their horseboxes onto the carriageway.[118][119][120]
The motorway has attracted unofficial, and illegal,motor racing. At the end of the 1980s, before the advent of automated speed enforcement devices, owners ofsupercars would meet at night at service stations such asSouth Mimms and conduct time trials.[121] Times below 1 hour were achieved – an average speed of over 117 mph (188 km/h), which included coming to a halt at theDartford Tunnel road user charge payment booths.[122][123] The winner received champagne rather than money. TheEnfield Gazette referred to an "M25 club", and posters appeared near the M25 advertising the "First London Cannonball Run".[121] The racing had mostly disappeared by the end of the 1980s after speed cameras were introduced.[124]
In 2021, several sections of the M25 were disrupted after the home energy and insulation campaign groupInsulate Britain blocked junctions including Nos. 3 (Swanley), 6 (Godstone), 14 (Heathrow), 20 (Kings Langley) and 31 (Lakeside). A spokesman forthe AA said the actions were counterproductive, as they would cause increased vehicle emissions owing to delays, as well having a negative effect on the economy.[125][126] 92 people were arrested following the first incident on 13 September, followed by a further 70 two days later. Insulate Britain said they would continue to disrupt the M25 until the government responded.[127]
On 29 October, two days before the2021 United Nations Climate Change Conference, Insulate Britain protests blocked traffic from junctions 21 to 22 in Hertfordshire and 28 to 29 in Essex. 19 arrests were made.[128]
The M25 is a form of social control to ensure disruptive elements in society are neutralised by keeping a significant proportion of them in continual motion.
The M25 and the Dartford Crossing are known for frequent traffic jams. This was noticed before the entire road had been completed; at the official opening ceremony Margaret Thatcher complained about "those who carp and criticise". The jams have inspired derogatory names, such as "Britain's Biggest Car Park"[130] and songs (e.g.,Chris Rea's "The Road to Hell").[131] Nevertheless, coach tours around the M25 have continued to run into the 21st century.[132]
The M25 plays a role in the comedy-fantasy novelGood Omens, as "evidence for the hidden hand of Satan in the affairs of Man".[16] The demon character, Crowley, had manipulated the design of the M25 to resemble a Satanicsigil, and tried to ensure it would anger as many people as possible to drive them off the path of good.[133][134] The lengthy series of public inquiries for motorways throughout the 1970s, particularly the M25, influenced the opening ofThe Hitchhiker's Guide to the Galaxy, where the Earth is destroyed to make way for a hyperspace bypass.[135]
The M25 enjoyed a more positive reputation amongravers in the late 1980s, when this new orbital motorway became a popular route to the parties that took place around the outskirts of London.[136] Its use for these raves inspired the name of the electronic duoOrbital.[16]
Iain Sinclair's 2002 book and filmLondon Orbital is based on a year-long journey around the M25 on foot.[137]
A piece ofgraffiti on theChalfont Viaduct, clearly visible from the M25 and reading "Give Peas a chance" (parodyingJohn Lennon's "Give Peace a Chance") became popular with the public, attracting its ownFacebook group.[138][139] The message originally read "Peas", supposedly the tag of a London graffiti artist; the rest of the wording is reported to have referred to his frequent clashes with the law.[140][141] In September 2018, after almost 20 years, the graffiti was vandalised and then removed and replaced with the message "Give Helch a break".[142] A spokesman forNetwork Rail sympathised with the requests to restore the "much-loved graffiti", but said they do not condone people putting their lives at risk by trespassing.[142][143]
Data fromdriver location signs provide carriageway identifier information.[144] The numbers on the signs are kilometres from a point on the north side of the Dartford Crossing, while the letter is "A" for the clockwise carriageway and "B" for the anticlockwise. They are spaced every 500 metres (1,600 ft).[27]
The M25 has been criticised for having too many junctions; 14 of them serve only local roads.[37][145] In 2016,Edmund King, president of theAutomobile Association, attributed congestion on the M25 to excessive junctions. This leads to "junction hoppers" who only use the motorway for a short distance before exiting;[146] their difference in speed when entering and leaving the main carriageway causes adomino effect, resulting in all vehicles slowing down.[147] Drivers who only use the M25 to travel a short distance are believed by some to have less overall driving experience, exacerbating traffic and safety issues.[146]
The M25 originally opened without any service areas. The first, atSouth Mimms, was opened by Margaret Thatcher in June 1987, a week before the election. Thatcher admired the practical and no-frills architecture ofCharles Forte and praised him in her opening speech.[148] The second,Clacket Lane, was opened byRobert Key, Minister for Roads and Traffic, on 21 July 1993.[149] Construction was delayed as the remains of aRoman villa were found on the site, requiring archaeological research.[150] The other service area between junctions isCobham, which opened on 13 September 2012.[25]
| A282 (Dartford Crossing) | |||||
| miles | km[144][d] | Clockwise exits (A carriageway)[144] | Junction | Anti-clockwise exits (B carriageway) | Opening date[48] |
|---|---|---|---|---|---|
| 0.0 | 0.0 | Dartford Crossing South (Queen Elizabeth II Bridge)  | River Thames | Dartford Crossing North (Dartford Tunnels) | November 1963 (west tunnel) May 1980 (east tunnel) October 1991 (bridge) |
| EnteringKent | EnteringEssex | ||||
| 3.5 | 5.7 | Swanscombe,Erith,BluewaterA206 | J1A[e] | Swanscombe, Erith A206 | September 1986 |
| 4.7 | 7.5 | DartfordA225 | J1B | No Exit | September 1986 |
| M25 | |||||
| 5.5 | 8.8 | London (SE & C),BexleyheathA2 Canterbury (M2) Ebbsfleet International  Non Motorway Traffic | J2 | London (SE & C), Bexleyheath,BluewaterA2 Canterbury (M2) Dartford (A225) Ebbsfleet International | September 1986 (northbound) April 1977 (southbound) |
| 8.7 | 14.0 | Dover,Channel Tunnel,MaidstoneM20 London (SE),SwanleyA20 | J3 | London (SE & C),Lewisham A20 Channel Tunnel, MaidstoneM20 | April 1977 (northbound) February 1986 (southbound) |
| 12.2 | 19.6 | BromleyA21 OrpingtonA224 | J4 | London (SE), Bromley A21 Orpington A224 | February 1986 |
| 16.3 16.4 | 26.2 26.4 | Sevenoaks,HastingsA21 | J5 | Dover,Channel Tunnel,Maidstone M26 (M20) Sevenoaks, Hastings A21 | July 1980 |
| EnteringSurrey | EnteringKent | ||||
| 21.0 | 33.8 | Clacket Lane services | Services | Clacket Lane services | July 1993 |
| 25.8 | 41.6 | Eastbourne,Godstone,CaterhamA22 Redhill,Westerham (A25) | J6 | Eastbourne, Godstone, Caterham A22 Westerham (A25) | November 1979 (eastbound) February 1976 (westbound) |
| 28.6 | 46.0 | Brighton,Crawley Gatwick  Croydon M23 | J7 | Croydon Brighton, Gatwick M23 | February 1976 |
| 31.9 | 51.4 | Reigate,SuttonA217 Kingston (A240) | J8 | Reigate, Sutton A217 Redhill (A25) | February 1976 (eastbound) October 1985 (westbound) |
| 38.5 39.5 | 62.0 63.5 | LeatherheadA243 Dorking (A24) | J9 | Leatherhead A243 Dorking (A24) | October 1985 |
| 42.6 43.2 | 68.6 69.5 | Cobham services | Services | Cobham services | September 2012 |
| 45.0 | 72.4 | Portsmouth,Guildford,London (SW & C) A3 | J10 | London (SW), Kingston, Guildford, Portsmouth A3 | October 1985 (eastbound) December 1983 (westbound) |
| 49.8 | 80.2 | WokingA320 ChertseyA317 | J11 | Chertsey A317 Woking A320 | December 1983 (southbound) October 1980 (northbound) |
| 52.1 | 83.8 | Basingstoke,Southampton Richmond M3 | J12 | The SOUTH WEST, Southampton London (SW & C), Richmond M3 | October 1980 (southbound) December 1976 (northbound) |
| EnteringBerkshire | EnteringSurrey | ||||
| EnteringSurrey | EnteringBerkshire | ||||
| 55.2 | 88.8 | London (W),Hounslow,StainesA30 | J13 | London (W), Hounslow, Staines A30 | November 1981 (southbound) August 1982 (northbound) |
| EnteringGreater London | EnteringSurrey | ||||
| 57.0 | 91.8 | Heathrow (Terminals 4, 5 & Cargo)A3113 | J14 | Heathrow (Terminals 4, 5 & Cargo)A3113 | August 1982 (southbound) September 1985 (northbound) |
| EnteringBuckinghamshire | EnteringGreater London | ||||
| 59.0 | 95.0 | The WEST,Reading,Slough London (W & C),Heathrow (Terminals 1, 2 & 3)M4 | J15 | London (W), Heathrow (Terminals 1, 2 & 3) The WEST, Slough, Reading M4 | September 1985 |
| 63.8 | 102.6 | Birmingham,Oxford Uxbridge,London (W) M40 | J16 | Uxbridge, London (W & C) Birmingham, Oxford M40 | September 1985 (southbound) January 1985 (northbound) |
| EnteringHertfordshire | EnteringBuckinghamshire | ||||
| 68.7 | 110.5 | Rickmansworth,Maple Cross A412 | J17 | Maple Cross A412 | January 1985 (southbound) February 1976 (northbound) |
| 69.9 | 112.5 | Amersham,ChorleywoodA404 | J18 | Amersham, Chorleywood, Rickmansworth A404 | February 1976 |
| 71.5 | 116.4 | WatfordA41 | J19 | Exit via J20 – Watford A41 | September 1976 |
| 73.5 | 118.2 | Aylesbury,Hemel Hempstead A41 | J20 | Aylesbury, Hemel Hempstead, Watford A41 | August 1986 |
| 76.3 | 122.8 | The NORTH Luton M1 | J21 | The NORTH Luton M1 | August 1986 |
| 76.9 | 123.7 | (M1 South) St Albans,London (NW & C)A405 | J21A | (M1 South) St Albans, London (NW & C), Watford A405 | August 1986 |
| 80.6 | 129.7 | St AlbansA1081 | J22 | St Albans A1081 | August 1986 |
| 83.3 | 134.0 | HatfieldA1(M) London (N & C)A1 BarnetA1081 South Mimms services | J23 | London (N & C) A1 Barnet A1081 HatfieldA1(M) South Mimms services | August 1986 (westbound) September 1975 (eastbound) |
| 85.9 | 138.2 | Potters BarA111 | J24 | Potters Bar A111 | September 1975 (westbound) June 1981 (eastbound) |
| EnteringGreater London | EnteringHertfordshire | ||||
| 91.4 | 147.1 | London (N & C) Enfield,HertfordA10 | J25 | London (N & C) Enfield, Hertford A10 | June 1981 (westbound) January 1984 (eastbound) |
| Holmesdale Tunnel | Tunnel | Holmesdale Tunnel | January 1984 | ||
| EnteringEssex | EnteringGreater London | ||||
| 94.9 | 152.7 | Waltham Abbey,LoughtonA121 | J26 | Waltham Abbey, Loughton A121 | January 1984 |
| Bell Common Tunnel | Tunnel | Bell Common Tunnel | January 1984 | ||
| 99.2 | 159.7 | Cambridge,Stansted,Harlow London (N & E) M11 | J27 | London (NE & C) Cambridge, Harlow, Stansted M11 | January 1984 (westbound) April 1983 (eastbound) |
| EnteringGreater London | EnteringEssex | ||||
| 107.1 | 172.4 | Chelmsford,London (E & C),RomfordA12 BrentwoodA1023 | J28 | Chelmsford A12 Brentwood A1023 | April 1983 |
| EnteringEssex | EnteringGreater London | ||||
| EnteringGreater London | EnteringEssex | 54°10′12″N2°44′15″W / 54.17005°N 2.73748°W /54.17005; -2.73748 | |||
| 109.9 | 176.8 | Southend,Southend Airport,BasildonA127 | J29 | London (E & C), Romford, Southend, Southend Airport, Basildon A127 | April 1983 (northbound) December 1982 (southbound) |
| EnteringEssex | EnteringGreater London | ||||
| 115.2 | 185.4 | Tilbury,Thurrock,Lakeside,London (E & C)A13 Thurrock services | J30 | London (E & C), Tilbury, Thurrock, LakesideA13 Thurrock services Non Motorway Traffic | December 1982 |
| A282 (Dartford Crossing) | |||||
| 115.9 | 186.6 | No Exit | J31 | Thurrock,LakesideA1306 Purfleet (A1090) West Thurrock (A126) Thurrock services | December 1982 |
| Dartford Crossing South (Queen Elizabeth II Bridge) | River Thames | Dartford Crossing North (Dartford Tunnels) | November 1963 (west tunnel) May 1980 (east tunnel) October 1991 (bridge) | ||
| EnteringKent | EnteringEssex | ||||
Notes
| |||||
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi | |||||
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).
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