The 'M25 motorway' is one of the
United Kingdom's motorways. It is an
orbital motorway, 117 miles (188 km) in circumference, that almost completely encircles
London (the gap is formed in the east, with the
Dartford Crossing or the
A282, linking two sides of the
River Thames). It is said to be one of the longest city bypasses in the world
[1]. In Europe, the M25 is the second-longest ring road after the Berlin Ring (
A 10) which is longer by 5 miles (8 km).
Description
For most of its length the motorway has six lanes (three in each direction), although there are a few short stretches which are four-lane and perhaps one sixth is eight-lane, around the south-western corner. The motorway was widened to ten lanes between junctions 12 and 14, and twelve lanes between junctions 14 and 15, in November 2005. The
Highways Agency has plans to widen almost all of the remaining stretches of the M25 to eight lanes.
It is one of
Europe's busiest motorways, with 196,000 vehicles a day recorded in 2003 between junctions 13 and 14 near
London Heathrow Airport (
[2]), significantly less, however, than the 257,000 vehicles a day recorded in 2002 on the
A4 motorway at
Saint-Maurice, in the suburbs of
Paris (
[3]), or the 216,000 vehicles a day recorded in 1998 on the
A 100 motorway near the
Funkturm in
Berlin (
[4]).
The M25 is not a continuous loop. To the east of London, the toll crossing of the
Thames between
Thurrock and
Dartford is the non-motorway
A282. The
Dartford Crossing, which consists of two tunnels and the
QE2 (Queen Elizabeth II) bridge, is named ''Canterbury Way''. Passage across the bridge or through the tunnels is subject to a toll, dependent upon the type of vehicle. Designating this stretch as a motorway would mean that traffic not permitted to use motorways could not cross the
Thames east of
Woolwich.
While this is more a structural than a logical issue, at junction 5 near
Sevenoaks continuing around the M25 requires the driver to follow the
slip roads, as the anticlockwise carriageway continues as the
M26 to the east (towards the
M20) and the clockwise as the
A21 towards the south coast.
The road passes through multiple police force areas. Junctions 1–5 are in Kent, 6–14 in Surrey (passing at places through Greater London and Berkshire), 15–16 are in Buckinghamshire, 17–24 are in Hertfordshire, 25 in Greater London, 26–28 in Essex, 29 in Greater London and 30–31 in Essex. Policing the road is carried out by an integrated policing group made up of the
Metropolitan,
Thames Valley,
Essex,
Kent,
Hertfordshire and
Surrey forces.
The distance of the motorway from central London (taken as
Charing Cross) varies from approximately 12 miles (20 km) near
Potters Bar to 20 miles (32 km) near Byfleet. In some places (Enfield, Hillingdon and Havering) the
Greater London boundary has been realigned to the M25 while in others, most notably in
Surrey, it is many miles distant.
North Ockendon is the only settlement of Greater London to be outside the M25. In 2004, following a poll, a move was mooted by the
London Assembly to entirely align the Greater London boundary to the M25.
[1]
The three service areas are located in the central north (JCT 23 South Mimms), south east (Clacket Lane) and central east (Thurrock).
History
The idea of an orbital road around London was first proposed early in the
20th century and was re-examined a number of times during the first half of the
20th century in plans such as
Sir Edwin Lutyens and
Sir Charles Bressey's ''The Highway Development Survey'',
1937 and
Sir Patrick Abercrombie's ''
County of London Plan,
1943'' and ''Greater London Plan, 1944''. Abercrombie's plan proposed a series of five roads encircling the capital.
In the post-war years little was done to implement Abercrombie's plans but in the
1960s the
Greater London Council developed an ambitious plan for a network of ring roads around the capital. The
London Ringways plan was hugely controversial due to the destruction required for the inner two ring roads and the enormous anticipated cost. The plan was modified a number of times to overcome opposition from the residents of threatened areas and the government, but was cancelled in
1973. Parts of the two outer ring roads, Ringways
3 and
4, were begun in 1973 and became the first two sections of the M25 to open in
1975 (junction 23 to junction 24) and
1976 (junction 6 to junction 8).
Construction of the M25 continued in stages until its completion in
1986. The stages were not constructed contiguously but in small sections, such as Dartford to Swanley (junction 1 to junction 3) and
Potters Bar to
Waltham Cross (junction 24 to junction 25). As the orbital road developed the sections were linked. Each section was presented to planning authorities in its own right and was individually justified, with almost 40 public inquiries relating to sections of the route. Maps at this time depicting these short sections named the route as the M16 but this changed before completion. The northern sections of the M25 follow a similar route to the
World War II Outer London Defence Ring.
The M25 was officially opened on
October 29 1986 with a ceremony by
Prime Minister Margaret Thatcher, who opened the section between J22 and J23 (
London Colney and
South Mimms).
The initial tenders for the construction of the M25 totalled £631.9 million. This did not include compulsory purchase of land and subsequent upgrades and repairs.
More recently, the perennially
congested south-western stretch of the M25 (near
Woking) has been fitted with an experimental automated traffic control system called
Motorway Incident Detection and Automatic Signalling (MIDAS). This consists of a distributed network of traffic and weather sensors,
speed cameras and
variable-speed signs that control traffic speeds with little human supervision. The system hasn't reduced congestion but it is hoped that MIDAS will be fitted to the rest of the M25 in due course anyway.
A precursor of the M25 was the ''North Orbital Road'' (see
A414 road).
Illuminated sections
Large sections of the M25 are illuminated with the aim of reducing accidents on the road. The current illuminated sections are Dartford to junction 2, junction 5, junctions 6 to 16, junctions 18 to 21A, and junctions 23 to 31. It is thought that when the widening of the M25 is completed junctions 3 to 5 will be the only area unlit, as this is the quietest part of the M25. The type of lights on the M25 varies, with some of the sections using the older yellow
low-pressure sodium (SOX) lighting, and others with modern high-pressure sodium (SON) lighting.
Some stretches have recently been upgraded to SON. These include Junction 5, junctions around Heathrow and 27.
Junctions
| 'M25 Motorway' |
| Clockwise exits | Junction | Anti-clockwise exits |
| Erith 'A206' | J1a | Swanscombe 'A206' |
| Dartford 'A225' | J1b | ''No Exit'' |
London, Canterbury 'A2', (M2), Bluewater Dartford ('A225') | J2 | London, Canterbury 'A2', ('M2'), Bluewater |
London (South East) 'A20' Maidstone 'M20' Swanley 'B2173' | J3 | Maidstone, Channel Tunnel, Dover 'M20' London (South East), Swanley 'A20' |
Bromley 'A21' Orpington 'A224' | J4 | Bromley 'A21' Orpington 'A224' |
Maidstone, Channel Tunnel, Dover 'M26' ('M20') Sevenoaks, Hastings 'A21' | J5 | Sevenoaks, Hastings 'A21' |
| ''Clacket Lane services'' | ||
East Grinstead, Eastbourne, Caterham, Godstone 'A22' Westerham ('A25') | J6 | East Grinstead, Eastbourne, Caterham, Godstone, 'A22' Redhill ('A25') |
| Gatwick Airport, Crawley, Brighton, East Grinstead, Croydon 'M23' | J7 | Gatwick Airport, Crawley, Brighton, Croydon 'M23' |
Reigate, Sutton 'A217' Redhill ('A25') | J8 | Reigate, Sutton 'A217' Kingston ('A240') |
Leatherhead 'A243' Dorking ('A24') | J9 | Leatherhead 'A243' Dorking ('A24') |
| London (South West), Kingston, Guildford, Portsmouth 'A3' | J10 | London (South West), Guildford 'A3' |
Chertsey 'A317' Woking 'A320' | J11 | Woking 'A320' Chertsey 'A317' |
| Basingstoke, Southampton, Richmond 'M3' | J12 | Basingstoke, Southampton, Richmond 'M3' |
| Staines 'A30' | J13 | London (West), Staines, Windsor 'A30' |
| Heathrow Airport (Terminals 4, 5 and Cargo) 'A3113' | J14 | Heathrow Airport (Terminals 4, 5 and Cargo) 'A3113' |
| The WEST, Slough, Reading, London (West), Heathrow Airport (Terminals 1, 2 and 3) 'M4' | J15 | The WEST, Slough, Reading, London (West), Heathrow Airport (Terminals 1 2, and 3) 'M4' |
| Birmingham, Oxford, Uxbridge, London (West) 'M40' | J16 | Birmingham, Oxford, Uxbridge, London (West) 'M40' |
| Maple Cross ('A412') | J17 | Maple Cross, Rickmansworth ('A412') |
| Rickmansworth, Chorleywood, Amersham 'A404' | J18 | Chorleywood, Amersham 'A404' |
| No Exit | J19 | Watford 'A41' |
| Hemel Hempstead, Aylesbury 'A41' | J20 | Hemel Hempstead, Aylesbury 'A41' 'A4251' |
| The NORTH, Luton & Airport 'M1' | J21 | The NORTH, Luton & Airport 'M1' |
Watford 'A405' Harrow ('M1 South') | J21A | St. Albans 'A405' London (North West) ('M1 (South)') |
| St. Albans 'A1081' | J22 | St. Albans 'A1081' |
Hatfield 'A1(M)' London (North West) 'A1' Barnet 'A1081' ''South Mimms services'' | J23 | Hatfield 'A1(M)' London (North West) 'A1' Barnet 'A1081' ''South Mimms services'' |
| Potters Bar 'A111' | J24 | Potters Bar 'A111' |
| Enfield, Hertford 'A10' | J25 | Enfield, Hertford 'A10' |
| Waltham Abbey, Loughton 'A121' | J26 | Waltham Abbey, Loughton 'A121' |
| London (North East), Stansted Airport, Harlow, Cambridge 'M11' | J27 | London (North East), Stansted Airport, Harlow, Cambridge 'M11' |
Chelmsford, Witham, Colchester 'A12' Brentwood 'A1023' | J28 | Chelmsford, Romford 'A12' Brentwood 'A1023' |
| Romford, Basildon, Southend 'A127' | J29 | Basildon, Southend 'A127' |
Thurrock (Lakeside), Tilbury 'A13' ''Thurrock services'' | J30 | Dagenham, Thurrock (Lakeside), Tilbury 'A13', ('A1306', 'A126', 'A1090') ''Thurrock services'' |
| South Ockendon, Dagenham 'A1306' | J31 | ''No Exit'' |
Map

Map of Ringways 3 & 4 showing sections combined to form the M25
Trivia
The M25 (including the A282 Dartford Crossing) is known for its frequent jams. These have been the subject of so much comment from such an early stage that even at the official opening ceremony Margaret Thatcher complained about "those who carp and criticise". The jams have inspired jokes ("the world's biggest car park", "the London Orbital Car Park"), songs (
Chris Rea's "The Road to Hell") and the following tongue-in-cheek theory:
:''"Many phenomena — wars, plagues, sudden audits — have been advanced as evidence for the hidden hand of
Satan in the affairs of
Man, but whenever students of
demonology get together the M25 London orbital motorway is generally agreed to be among the top contenders for exhibit A."
::— from ''
Good Omens'', by
Terry Pratchett and
Neil Gaiman.''
This is because (in the book) the M25 was actually moulded by demonic forces during its planning so as to resemble, from space, a mystic demonic sigil.
The M25's name inspired the name of the
electronica duo,
Orbital.
A Bit of Fry and Laurie comedy show's This is Dominic Appleguard skit presents Dominic Appleguard as a man of many psychological disfunctions, finally declaring that he designed M25.
The motorway's dubious reputation once prompted
Andy Hamilton to say, in reference to the M25, "abandon hope all ye who enter here; no services until Junction 12".
References
★
Iain Sinclair, ''London Orbital: A Walk Around the M25'', 2002, Granta Books, ISBN 1-86207-547-6
★
Roy Phippen, ''Travelling M25 Clockwise'', 2005, Pallas Athene, ISBN 1-873429-90-8
1. London Assembly - ''Poll says M25 is London's "natural boundary"''. 2 March 2004.
See also
★ Berlin
A10
★ Dublin
M50
★ Manchester
M60
★ Paris
Périphérique
★ Paris
A86_autoroute
★ Rome
Grande Raccordo Anulare
★ Moscow
MKAD
External links
★
The Motorway Archive's M25 page
★ CBRD
★
★
Motorway Database — M25
★
★
Histories - Opening Booklets, including M25