The M40 motorway links London, Oxford, and Birmingham in England, a distance of about .
The motorway is dual three lanes except for junction 1A to junction 3 (which is dual four lanes) a short section in-between the exit and entry slip-roads at junction 4 (which is two lanes in both directions) and also between the slip-roads at junction 9 (in the south-eastbound direction only).
An Active Traffic Management system operates on the short section north-westbound from junction 16 (A3400) to the M42.
History London to Great Milton The motorway between London and Oxford was constructed in stages between 1967 and 1974. The first section opened in June 1967, from Handy Cross roundabout, High Wycombe to Stokenchurch (junctions 4–5). In 1969, extending in a southerly direction to Holtspur, Beaconsfield, a temporary junction 2 was opened. The section bypassing Beaconsfield was built in 1971 and the section past Gerrards Cross to junction 1 was completed in 1973. In 1974, the motorway between junctions 5 to 8 was completed to Great Milton.
Between junctions 3 and 4, the beginnings of slip roads were built on both carriageways for a service area at Abbey Barns between Beaconsfield and High Wycombe. Beaconsfield services off junction 2 opened in 2009.
Great Milton to Birmingham Late in the 1960s, not long after the first stretch opened, the Ministry of Transport announced the possibility of building a new motorway to link London with Birmingham as an alternative to the M1M6 routeas well as improving road links to the South Coast ports for The Midlandsbut it was not until December 1984 that the decision to extend the M40 from Oxford to the south of Birmingham was given the go-ahead, with the anticipation of the route being built in three phases and being fully operational by 1990.
The preferred route was altered to avoid Otmoor after a vigorous road protest, which included selling over 3,000 small squares of a field to people all over the world. The field had been renamed 'Alice's field' as a reference to Alice in Wonderland by Lewis Carroll who lived in the area at the time of the book's writing.
Construction began at Warwick in October 1987, with work on the section around Banbury starting in February 1988, and finally, the section north of Oxford in July 1989. The 12-mile section between the M42 and Warwick opened in December 1989, and the remaining 48-mile section in January 1991. The section between Banbury and Warwick had been completed several months earlier, but its opening was delayed until the Banbury to Oxford section was ready, to avoid the inevitable congestion of A-roads in north Oxfordshire towards the end of 1990 that an earlier opening would have caused.
At the time of being fully opened, the original M40 had been widened, creating a dual three-lane motorway from start to finish, with the exception of the Handy Cross underpass, which remains dual two-lane.
Further developments
The M40 had been expected to be the last major motorway to be built in Britain, but in 1986 the Conservative government announced a major new road-building scheme, Roads for Prosperity, much of which was cancelled in 1996 after major road protests.
Beginning in 1997, the motorway was widened to dual-four-lane between J1A and J3 (High Wycombe East) under a Private Finance Initiative. It was completed by a Carillion-John Laing joint venture in October 1998 – the original plan included widening between J3 and J4. Oxford services and Warwick Services opened in 1998.
Work to separate local and long-distance traffic at J4 was completed in 2007, including a new dedicated left-turn slip lane between the A404 Marlow Bypass and the Oxford-bound M40; additional lanes on the slip roads entering the roundabout; an additional lane between the A404 Marlow Hill and the London-bound M40; and a five-lane cross-link between the M40 and the A404(S).
In 2009 the Highways Agency extended the Active Traffic Management (ATM) system onto the northbound carriageway from J16 to the junction with the M42. Beaconsfield services opened in 2009, near the site of the service station proposed at Abbey Barns almost 40 years earlier.
In August 2010 work started on J9, upgrading the southbound exit slip road to three lanes, and similar widening on the connecting A34 and A41 junctions between Oxford and Bicester. This was the first part of the work at this busy junction since it was built 20 years earlier. If the necessary funding becomes available, a second phase of improvement will be carried out, upgrading the northbound entrance and the A41 southbound entrance.
Route
Main towns/cities served The following table only includes places situated near the motorway and those close enough to be considered 'near the motorway' (like Aylesbury). Other places that may use the motorway (for access to the north) are not included as they have other motorway access (for example Slough). Small villages are not included. Population figures are based on the 2001 census by the Office for National Statistics +Settlements on M40 corridorPlacePopulationCeremonial countyMain railway stationMotorway junctionGerrards Cross/Chalfont St Peter19,622BuckinghamshireGerrards Cross1,2Beaconsfield10,679BuckinghamshireBeaconsfield2High Wycombe Urban Area118,229BuckinghamshireHigh Wycombe3,4Thame10,886OxfordshireHaddenham & Thame Parkway7,8AOxford134,248OxfordshireOxford8,8ABicester28,672OxfordshireBicester North9Aylesbury Urban Area69,021BuckinghamshireAylesbury7,8A,9Banbury43,867OxfordshireBanbury11Leamington Spa45,114WarwickshireLeamington Spa13,14,15Warwick25,434WarwickshireWarwick15Stratford-upon-Avon23,676WarwickshireStratford-upon-Avon15
List of junctions
+M40 motorway junctionsmilekmSouthbound exits (B carriageway)JunctionNorthbound exits (A carriageway)Coordinates18.1 29.2 End of motorwayRoad continues as A40 to London J1 Start of motorwayRoad formed from main carriageways of A40 from London Slough (A412) Uxbridge (A4020) Amersham, Denham A40Slough (A412)Non-motorway traffic19.920.4 32.0 32.9 M25Watford, Stansted , (M1, (A1(M)), M11)Heathrow , (M4, M3, M23) J1aPartial cloverleaf interchange M25Heathrow , (M4, M3)Watford, Stansted (M1, A1(M), M11) 24.825.3 39.9 40.7 Beaconsfield, Amersham, Slough A355, Beaconsfield services Extra J2Services Beaconsfield, Amersham, Slough A355, Beaconsfield services Extra 27.828.1 44.7 45.2 No Exit J3 High Wycombe (E) A40 31.331.6 50.3 50.9 High Wycombe, Marlow, Maidenhead A404 (M4) J4 High Wycombe, Marlow A404 (M4) 38.939.3 62.6 63.2 Stokenchurch, West Wycombe A40 J5 Stokenchurch A40 Entering Buckinghamshire Entering Oxfordshire 41.441.8 66.7 67.2 Watlington, Princes Risborough B4009 J6 Watlington, Princes Risborough B4009 47.047.4 75.6 76.2 No Exit J7 Thame, Wallingford, A329 48.048.4 77.3 77.9 No Exit J8 Oxford, Cheltenham A40 49.049.2 78.9 79.2 Thame, Aylesbury A418Oxford (A40)Oxford services Welcome Break J8aServices Aylesbury A418Oxford (A40)Oxford services Welcome Break Entering Oxfordshire Entering Buckinghamshire Entering Buckinghamshire Entering Oxfordshire 60.360.6 97.1 97.6 Bicester, Aylesbury A41 Oxford, Newbury A34 J9 Newbury, Oxford A34Bicester A41 65.966.2 106.0 106.6 Northampton, Milton Keynes A43Middleton Stoney B430, Cherwell Valley services Moto J10Services Northampton A43Middleton Stoney B430Cherwell Valley services Moto Entering Oxfordshire Entering Northamptonshire Entering Northamptonshire Entering Oxfordshire Entering Oxfordshire Entering Northamptonshire Entering Northamptonshire Entering Oxfordshire 76.276.7 122.7 123.4 Banbury A422 (A361) J11 Banbury A422 (A361) Entering Oxfordshire Entering Warwickshire Entering Warwickshire Entering Oxfordshire Entering Oxfordshire Entering Warwickshire 86.887.0 139.7 140.0 Gaydon B4451 J12 Gaydon B4451 89.8 144.5 Warwick Services Welcome Break Services Warwick Services Welcome Break 92.192.3 148.2 148.6 No Exit J13 Leamington, Warwick A452 (A425) 93.994.2 151.1 151.6 Leamington A452 J14 No Exit 95.095.3 152.9 153.4 Warwick A429 Stratford, Coventry, Warwick Parkway A46 J15 Coventry, Stratford, Warwick Parkway A46Warwick A429 103.8104.1 167.1 167.6 Henley A3400 J16 No Exit 105.7106.0 170.1 170.6 Start of motorwayMotorway is formed by two sliproads from the M42 J17(M42, J3a) End of motorway M42The NORTH (M1, M6), Birmingham (E, N & C), Solihull, N.E.C, Airport & International The SOUTH WEST (M5), Birmingham (S & W), Redditch
Data from driver location signs are used to provide distance and carriageway identifier information. Where a junction spans several hundred metres, both start and end locations are given.
An Active Traffic Management system operates on the short section northbound from junction 16 (A3400) to the M42.
Services The motorway has four service areas: Beaconsfield services (off J2), operated by Extra MSA accessible from the A355 Oxford services (off J8A), operated by Welcome Break, accessible from J8 and the A418 Cherwell Valley services (off J10, A43), operated by Moto. Warwick services (between J12 and J13), operated by Welcome Break, consisting of two sites mirroring each other without a connection.
A motorway service station was proposed at Abbey Barn to cost £700,000, south of High Wycombe in November 1973, north of Little Marlow, next to the former Wycombe Summit.Times Monday 12 November 1973, page 8 A similar motorway service station was proposed at Hensall, North Yorkshire on the (unbuilt) M62 in December 1973, and which likewise was neither built.Times Wednesday 5 December 1973, page 30
Detailed route description
Junction 1 of the M40 is at the Denham Roundabout near Uxbridge just east of the M25. The motorway is carried over the top of the roundabout, which interchanges with the A40, the A412, the A4020 and links to the A413 off the A40 westbound.
The motorway carries on for another before it reaches junction 1a, the free-flow interchange with the M25 London Orbital. It is a partially unrolled cloverleaf, with the smoothest turns from the London-bound M40 (from Oxfordshire, Warwickshire and the wider West Midlands) to the anti-clockwise M25 (London Heathrow, Gatwick, The Channel Ports) and vice versa, since this is the largest exchange of traffic between the two motorways. The M40 passes over the interchange, with the M25 on the bottom. The clockwise M25 enters the junction with four lanes with a lane drop to accommodate traffic heading for the M40 westbound, leaving the junction with three lanes. The anti-clockwise M25 enters the junction with three lanes and gains a lane from the London-bound M40 to accommodate the extra traffic. The London-bound M40 enters with four lanes, with a lane drop for the M25 exit, leaves with three lanes, and the westbound M40 enters with lanes and gains a lane from the anti-clockwise M25.
After junction 1a the motorway is four lanes, and carries on for until it reaches junction 2 for the A355 to Slough and the A40 to Beaconsfield and Gerrards Cross. Junction 2 is the standard roundabout interchange over the M40. Beaconsfield services are located at this junction.
Junction 3 is further on, and serves the A40 for High Wycombe East and Loudwater. This is a restricted junction; the only flows are from the westbound M40 to the A40 and from the A40 to the London-bound M40. The westbound carriageway loses a lane, remaining three lanes for the rest of the route, and the London-bound carriageway gains a lane. The motorway then immediately crosses the valley on a large ramp-like bridge.