|Location Map ( geo)|
|From:||Fleet Downs, near Dartford (TQ557728)|
|Via:||Leatherhead, Heathrow, Watford|
|Distance:||117 miles (188.3 km)|
|Meets:||A282, A2, M20, M26, M23, A3, M3, M4, M40, A41, M1, A405, A1, A1(M), A10, M11, A12, A13, A282|
|Former Number(s):||M16, A6, A405, A1178|
|Old route now:||M26|
|Route outline (key)|
The M25 is one of the nation's busiest motorways, carrying up to 200,000 vehicles and 10,000 HGVs per day (AADT) near to Heathrow Airport. Since its opening in the 1980s, the southern, western and eastern sections have been widened to largely D4M standard, but much of the motorway retains its D3M cross-section as originally built. The M25 was home to England's first Variable Speed Limits on motorways between the A3 and M4 in the early 1990s.
- 1 Route
- 2 History
- 3 Traffic Data
- 4 Services
- 5 Junctions
- 6 Links
The M25 forms most of a circle between Dartford in Kent and Thurrock in Essex, surrounding Greater London. On the way it passes Sevenoaks, Reigate, Redhill, Heathrow Airport, Watford, Potters Bar and Brentwood. Most of the motorway is now four lanes wide, and large sections of it are subject to Active Traffic Management.
The M25 as constructed is part of two separately planned motorways, M25 Ringway 4, and M16 Ringway 3. The linking sections between the two projects are located between junctions 3 and 5; and between junctions 19 and 23. Due to this change in plan, parts of M25 opened with the numbers A405 and A1178. The M25 is slightly shorter than Germany's A10 Berliner Ring.
|Section||2002 AADF||2006 AADF||2010 AADF||2014 AADF|
Clacket Lane services
Clacket Lane is located on the southern side of the M25, between M23 and M26. It is unusually named after the road that runs over the M25 at this point, and was at one time famous for its expensive fuel.
Cobham services is a single-site MSA situated on the southern side of the M25 but serving both directions, located 5 miles southeast of J10 for the A3. It was opened in 2012 and is the most recent services opened on the motorway.
South Mimms services
South Mimms is a single-site MSA shared with the A1(M). It was the first MSA to open on the M25, and was rebuilt in the late 1990s.
List of M25 Named Junctions
All of the junctions on the M25 have names.
Bignell's Corner is a large three-level roundabout interchange providing full access between the M25, A1(M), A1081, South Mimms services and local roads. It is junction 1 of the A1(M), and junction 23 of the M25. The A1(M) passes underneath the roundabout in a north-south direction at the lowest level, with the M25 passing over the roundabout at the highest level in an east-west direction.
The Chevening Interchange is a restricted access freeflow interchange between the M25, M26 and A21 northwest of Sevenoaks. It is notorious for requiring a TOTSO for M25 traffic, and having no turn offs for the M26 westbound and A21 northbound.
The Chiswell Interchange is a major junction between the M1 and M25 motorways near St Albans in Hertfordshire. The junction is a modified directional-T style interchange, with the modification being that instead of terminating, the M1 continues through the junction. No links from or to the southern M1 are provided. These are instead provided by the nearby A405 link between M25 junction 21A and M1 junction 6.
The Merstham Interchange is the junction between the M25 and the M23. It is one of three four-level stacks in the United Kingdom. The junction is only a mile south of the terminus of the M23, the Hooley Interchange. Consequently, very little traffic heads north from here.
- Motorway Database: M25
- Futures: M25 J12-15 Widening
- Futures: M25 Holmesdale Tunnel Refurbishment
- Futures: M25 & A2 Widening
- Futures: M25 J16-23 Widening
- Futures: M25 J27-30 Widening
Motorway Services Online
- Services List: Clacket Lane
- Services List: Cobham
- Services List: South Mimms
- Services List: Thurrock
- M25 J16-23 widening project (2009-11) (National Archives)
- Driver Location Signs Map (National Archives)
- M25 South West Quadrant Strategic Study - Stage 3 - March 2016 (archive.org)
- M25 South West Quadrant - Evidence Report - March 2016 (archive.org)
- Post Opening Project Evaluation - M25 Junctions 5-7 Smart Motorway–One Year After January 2020 (archive.org)
- Post Opening Project Evaluation - M25 Junctions 23-27 Smart Motorway–One Year After March 2020 (archive.org)
- The M25 Motorway (A13 to A12 Section and Connecting Roads) Scheme 1975 - Original legislation allowing construction of A13 to A12 section
- The M25 Motorway (Junction 5) (50 Miles Per Hour Speed Limit) Regulations 2020 - These Regulations introduce a 50 miles per hour speed limit on a length of the clockwise carriageway of the M25 motorway at junction 5 which merges with the south-westbound carriageway of the M26 motorway.
- The M25 Motorway (Junctions 10 to 15) (Variable Speed Limits) Regulations 1995 - These are revoked by the 2001 regulations.
- The M25 Motorway (Junctions 10 to 16) (Variable Speed Limits) Regulations 2001 - These are revoked by the 2012 regulations.