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The M3 motorway runs in England for approximately Template:Convert/mi from Sunbury-on-Thames, Surrey, to Southampton, Hampshire and forms an unsigned section European route E05. It is dual three lanes as far as Junction 8 (A303 road) near Basingstoke and then dual two lane until Junction 9 near Winchester and then dual three lane to Southampton. It was opened in sections starting in 1968 and was eventually completed in 1995 in the face of widespread opposition to the section past Winchester that now passes through Twyford Down.


See also: Twyford Down

Originally conceived as the 'London to Basingstoke Motorway',[1] the road was built to relieve traffic on the A30 and A33, the congested single carriageway trunk roads that previously carried the traffic.

The first section, from Sunbury-on-Thames in Surrey to Popham near Basingstoke opened between in sections, first the Hampshire section in 1971 and then the Surrey section in 1974[2] at a cost of £46m[3] and by 1967 the A33 road from Popham to the eastern end of the Winchester Bypass was being widened to dual carriageway.[4]

The first public inquiry for the 'M3 London to Basingstoke Motorway: Popham to Compton' extension[5] of the motorway which include the section past Winchester was held in 1971.[6]

A second public inquiry into the extension[7] was held in 1976-7.[6] The earlier decision to route the motorway through or alongside the water meadows between St Catherine’s Hill was reopened and during the year-long inquiry the Headmaster of Winchester College was forcibly ejected along with others for causing a disturbance.

The scope of the extension was reduced to defer the difficult decision about the section around Winchester and it was built in two sections (from 'Popham to Bridget's Farm' and from 'Bridget's Farm to Bar End') in 1985.[2] When it was opened the temporary junction to the A33 was removed.

File:M3 - East Stratton.jpg

The M3 motorway at East Stratton

File:M3 - Southampton.jpg

Southern end of the M3 motorway, meeting the A33 at Southampton

File:Twyford down.jpg

The M3 under construction at Twyford Down

The section from near Junction 12 (Eastleigh and Chandler's Ford) to the M27 motorway (Junction 4) followed the route of the A33 road which was upgraded to motorway standard and opened in 1991.[6]

An additional junction, numbered 4a, opened in April 1992 near Farnborough[8]

This left the unresolved issue of the route of the final section past Winchester. A tunnel design was proposed, but rejected. The final route, though Twyford Down resulted in major road protests between 1991 and 1995 when the final section of the motorway was finally opened.[2] On opening of the extension the old Winchester Bypass, which had been constructed in the 1930s, was closed and reverted to rich grassland.[9]

By 2008 the busiest section (at Chandler's Ford) was carried a daily average of around 130,000 vehicles.[10]

Detailed routing[]

The motorway starts as a dual three lane route at Sunbury on Thames on the edge of South West London. It heads south west, crosses the River Thames on the M3 Chertsey Bridge to the north of Chertsey and passes under the M25 motorway, before continuing in a more westerly direction south of Camberley. From Junction 4 it runs across the northern suburbs of Farnborough it enters a more rural setting, crosses the South Western Railway Main Line, and passes close to the Basingstoke Canal before reaching the outskirts of Basingstoke. Turning south west again, it runs across the south of Basingstoke, before reaching Junction 8, where lane 1 becomes the A303 road and the motorway continues as a dual two lane road through open countryside and Micheldever Wood until it reaches the north of Winchester.

Forming the Winchester Bypass it widens to three lanes at Junction 9, continues directly south and then into a small loop around the east of the City. It runs through a deep cutting in Twyford Down and then proceeds south west again, crossing the South Western Railway Main Line a second time alongside the River Itchen and back into a more urban environment before crossing the Eastleigh to Romsey railway line and ending at the Chilworth Roundabout on the fringes of Southampton.

A private exit off the northern roundabout at Junction 4a used to provided access to the UK headquarters of Sun Microsystems, however now this has been converted into a housing estate.[11] The A325 has a roundabout junction with a minor road over the M3 between junctions 3 and 4, but there is no junction with the motorway.


In the early morning of 25 April 1999, the drum and bass DJ and record producer known as Kemistry was killed on the M3 near Winchester by the steel body of a cat's eye, which had been dislodged by a van and flew through the windscreen of the following car in which she was a passenger. The coroner recorded a verdict of accidental death.[12] A question was asked in the House of Lords about the safety of cat's eyes in light of the highly unusual incident, and the Highways Agency conducted an investigation into the "long-term integrity and performance" of various types of road stud.[13]

On 1 April 2000, pranksters painted a zebra crossing across three lanes of the M3 between junctions 4 and 4a on the northbound carriageway near Farnborough in Hampshire.[14]


Data[15][16] from driver location signs are used to provide distance and carriageway identification information.

M3 Motorway
km Northeastbound exits (B Carriageway) Junction Southwestbound exits (A Carriageway)
24.2 Road continues as A316 to London J1 Sunbury, Kingston A308
24.6 Sunbury, Kingston A308 Start of motorway
34.2 Gatwick (M23), Maidstone (M20)
Stansted (M11), The NORTH (M1), Heathrow (M4), Chertsey (A320), Staines (A30) M25
J2 Gatwick (M23), Maidstone (M20)
Stansted (M11),The NORTH (M1), Heathrow (M4), Chertsey (A320), Staines (A30) M25
45.2 Woking, Bracknell, Bagshot, Lightwater A322 J3 Woking, Bracknell, Bagshot, Lightwater A322
52.5 Guildford, Farnham, Camberley,
Farnborough, Aldershot A331
J4 Guildford, Farnham, Camberley,
Farnborough, Aldershot A331
55.4 Farnborough (West) A327
Fleet (A3013)
J4a Farnborough (West) A327
Fleet (A3013)
Fleet services Services Fleet Services
67.4 Hook A287 (B3349) J5 Hook A287 (B3349)
75.0 Basingstoke, Newbury, Alton A339
Reading (A33)
J6 Basingstoke, Newbury, Alton A339
83.3 Basingstoke A30 J7 Basingstoke A30
85.5 No exit J8 The SOUTH WEST, Andover, Salisbury A303
96.4 Winchester services Services Winchester Services
102.8 The MIDLANDS, Newbury A34,
Winchester North
J9 Winchester (B3330)
105.0 Winchester (City) B3330
Alton A31
J10 No exit
108.1 Winchester B3335
Romsey A3090
J11 Winchester A3090
Twyford B3335
112.6 Eastleigh (North) A335 J12 Eastleigh (North), Chandler's Ford A335
115.6 Eastleigh, Chandler's Ford A335 J13 Eastleigh A335
Start of motorway
No exit
J14 Airport, Portsmouth M27 (East), The WEST, Southampton Docks, Bournemouth M27 (West), Southampton A33

See also[]


  1. THE M.3 MOTORWAY. Hansard (1967).
  2. 2.0 2.1 2.2 M3 London to Southampton Route Management Strategy. Department for Transport.
  3. M3 (Sunbury-Popham). Hansard (1988).
  4. The M3 Motorway. Hansard (1967).
  5. M3 London to Basingstoke Motorway: Popham to Compton public inquiry. National Archives.
  6. 6.0 6.1 6.2 M3. London to Southampton. The Motorway Archive.
  7. M3 London to Basingstoke motorway: Popham to Compton; public inquiry 1976. National Archives.
  8. Highways Agency – M3 London to Southampton Route Management Strategy. Highways Agency.
  9. Taming The Tarmac: The Lesson of Twyford Down. Cambridge University.
  10. Annual Average Daily Traffic Flows. Department for Transport. Retrieved on 28 September 2009.
  11. Off Site Highway Works and Contributions - Report of the County Surveyor. Roads & Development Sub-committee. Hampshire County Council (26 October 1998). Retrieved on 2008-03-23.[dead link]
  12. Kemistry. Fuller Up, the Dead Musician Directory. Retrieved on 2 December 2008.
  13. Template:Cite hansard
  14. Template:Cite news
  15. Area 3 Driver Location Signs (map) - Highway Authority, 2009
  16. Carriageway identifiers verified in situ on 2009-07-08

External links[]



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