M25 motorway
{{UK motorway routebox| motorway= M25
length-mi= 117 | length-km= 188 | direction= Circular | start= Dartford | destinations= London
Dartford
Bromley
Sevenoaks
Gatwick Airport
Reigate
Dorking
Esher
Staines
Heathrow Airport
Watford
Hemel Hempstead
Stansted Airport | end= West Thurrock | opening-date= 1975 | completion-date= 1986 | junctions= 3 - M20 motorway
5 - M26 motorway
7 - M23 motorway
12 - M3 motorway
15 - M4 motorway
16 - M40 motorway
21 - M1 motorway
23 - A1(M) motorway
27 - M11 motorway | The M25 motorway looking south between junctions 14 and 15, near Heathrow Airport. The red light from the overhead gantry, just visible in the distance, is the MIDAS system indicating a reduced speed limit due to congestion |
| The M25 between junction 24 (Potters Bar) and 25 (Waltham Cross). |
The M25 motorway is one of the United Kingdom's motorways. It is an orbital motorway, 117 miles (188 km) in circumference, that encircles London. It is said to be one of the longest city bypasses in the world. In Europe the M25 is the second-longest ring road after the Berlin Ring (A 10).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 ([1]), 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 ([2]), or the 216,000 vehicles a day recorded in 1998 on the A 100 motorway near the Funkturm in Berlin ([3]).
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 a bridge, is named Canterbury Way. Designating this stretch as a motorway would mean that traffic not permitted to use motorways could not cross the Thames below 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 main routes continue as either the M26 to the east (on to the M20) or 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 idea of an orbital road around London was first proposed early in the 20th century, through the Lutyens and Bressey plans of 1937 to the Abercrombie Plan of 1945 which proposed a series of five individual roads around the capital. Over time successive governments reduced this grandiose scheme to the Greater London Development Plan, a combination of two rings — the M25 and a smaller inner ring, initially hoped to become the M15, but currently still the A406 in the north, and the A205 in the south. These two elements of the inner ring road are known locally (and sign-posted) as the "North Circular Road" and the "South Circular Road" respectively.
The orbital was constructed in stages from around 1975 until 1985. The sections were not constructed contiguously but in small sections, such as Dartford to Swanley (junction 1 to junction 3) and Potters Bar to Waltham Cross (J24 to J25), and later joined. Each section was presented to planning authorities in its own right and was individually justified; there were 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 prior to completion. The north sections of the M25 follow a similar route to the World War II Outer London Defence Ring.
The M25 was officially opened in October 1986 with a ceremony by Margaret Thatcher opening 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 has reduced congestion and it is hoped that MIDAS will be fitted to the rest of the M25 in due course.
The M25 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"), 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.
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 the Greater London boundary has been aligned to the M25 while in other places, most notably in Surrey, it is many miles distant. North Ockendon is the only settlement of Greater London to be outside the M25. A move has been mooted by London mayor Ken Livingstone to entirely align the boundary to the M25. This idea is unlikely to get off the ground as it would face stiff opposition in Surrey.
The M25's name inspired the name of the electronica duo, Orbital; a pre-cursor of the M25 was the North Orbital Road''.*Iain Sinclair, London Orbital: A Walk Around the M25, 2002, Granta Books, ISBN 1862075476
*Roy Phippen, Travelling M25 Clockwise, 2005, Pallas Athene, ISBN 1873429908*Dublin M50
*Paris Périphérique
*Manchester M60*The Motorway Archive's M25 page
* CBRD Motorway Database — M25
*Gimpo's 25 Hour M25 Spin{| border=1 cellpadding=2 style="margin-left:1em; margin-bottom: 1em; color: black; border-collapse: collapse; font-size: 95%;"|- align="center" bgcolor="0080d0" style="color: white;font-size:120%;" | M25 Motorway | | Anticlockwise exits | Junction | Clockwise exits |
| Erith A206 | J1a | Swanscombe (A206) |
| Dartford A225 | J1b | No Exit |
| London, Canterbury A2, Dartford (A225) | J2 | London, Canterbury A2, (M2) |
| London A20, Maidstone M20, Swanley B2173 | J3 | Maidstone, Channel Tunnel, Dover M20, London SE, Swanley A20 |
| Bromley A21, Orpington A224 | J4 | Bromley A21, Orpington A224 |
| Maidstone, Channel Tunnel, Dover M26 (M20), Sevenoaks, Hastings A21 | J5 | Sevenoaks, Hastings A21 |
| East Grinstead, Eastbourne, Caterham, Godstone A22, Westerham (A25) | J6 | East Grinstead, Eastbourne, Caterham, Godstone, A22, Redhill (A25) |
| Gatwick Airport, Crawley, Brighton, East Grinstead 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 (SW), Kingston, Guildford A3 | J10 | London (SW), Guildford A3 |
| Chertsey A317, Woking A320 | J11 | Woking A320, Chertsey A317 |
| Basingstoke, Southampton, Sunbury M3 | J12 | Basingstoke, Southampton, Sunbury M3 |
| Staines A30 | J13 | London (W), Staines A30 |
| Heathrow Airport (T4, 5 and Cargo) A3113 | J14 | Heathrow Airport (T4, 5 and Cargo) A3113 |
| The WEST, Slough, Reading, London (W), Heathrow Airport (T1, 2, and 3) M4 | J15 | The WEST, Slough, Reading, London (W), Heathrow Airport (T1, 2, and 3) M4 |
| Birmingham, Oxford, Uxbridge, London (W) M40 | J16 | Birmingham, Oxford, Uxbridge, London (W) 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 S) | J21A | St. Albans A405, London (NW) (M1 S) |
| St. Albans A1081 | J22 | St. Albans A1081 |
| Hatfield A1(M), London (NW) A1, Barnet A1081 | J23 | Hatfield A1(M), London (NW) A1, Barnet A1081 |
| Potters Bar A111 | J24 | Potters Bar A111 |
| Enfield, Hertford A10 | J25 | Enfield, Hertford A10 |
| Waltham Abbey, Loughton A121 | J26 | Waltham Abbey, Loughton A121 |
| London (NE), Stansted Airport, Harlow, Cambridge M11 | J27 | London (NE), Stansted Airport, Harlow, Cambridge M11 |
| Chelmsford, Witham, Colchester A12, Brentwood A1203 | J28 | Chelmsford, Romford A12, Brentwood A1023 |
| Romford, Basildon, Southend A127 | J29 | Basildon, Southend A127 |
| Thurrock (Lakeside), Tilbury A13 | J30 | Dagenham, Thurrock (Lakeside), Tilbury A13, (A1306, A126, A1090) |
| South Ockendon, Dagenham A1306 | J31 | No Exit |
