The motorway is dual three-lane, except from Junction 8 (A303 road) near Basingstoke to Junction 9 near Winchester where it is dual two-lane. It was opened in sections starting in 1968 and was eventually completed in 1995 in the face of widespread opposition to the short section southeast of Winchester that passes through Twyford Down.
The M3 was originally approved as the "London to Basingstoke Motorway", as there was insufficient money to take it all the way across Hampshire to Southampton. the road was built to relieve two single carriageway trunk roads that were congested: the A30 eastern stretch to the A303 road and the Winchester to Southampton road.
In 1967, sections of the A33 road from Popham, Hampshire, to a north-eastern point of the Winchester Bypass were widened to dual carriageways; this only partially alleviated growing congestion, especially in Winchester, which led to the southern phase gaining approval.
The eastern section, from Sunbury-on-Thames in Middlesex to Popham near Basingstoke opened in sections: first the Hampshire section in 1971, and then the Middlesex and Surrey section in 1974. The cost for this first phase was £46m. The completed road acts as a continuation of the A316 'Country Way', an express three-lane road from Apex Corner, Hanworth in Middlesex to Sunbury-on-Thames.
A first public inquiry for the "M3 London to Basingstoke Motorway: Popham to Compton extension" centred on the section passing Winchester, and was held in 1971, after which the ministry was instructed to reconsider and reconsult on the proposals. A second public inquiry was held in 1976–77. The earlier decision to route the motorway through or alongside the water meadows between St Catherine's Hill and the compact cathedral city 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 M3 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 1995. When this opened, the temporary junction to the A33 parallel route was removed.
The section of the M3 from near Junction 12 (Eastleigh and Chandler's Ford) to the last, Junction 14 for the M27 replaced part of the A33 road which was upgraded to motorway standard and opened in 1991.
The southern section starts as a continuation of a single-lane avenue, Bassett Avenue and The Avenue by Southampton as the M27 motorway provides alternative routes from other parts of the city, particularly its waterfront and downtown peak-hour accessway, the M271 motorway and Mountbatten Way providing dual to three lane highways starting at the north-west of the city.
The M3 starts at Sunbury-on-Thames in Middlesex, at the edge of the metropolitan conurbation, as the continuation of the A316 which has three lanes each way from Hanworth (and two from Richmond Circus in Twickenham). The motorway 2 miles after its start turns more west-southwest, crosses the River Thames into Surrey on the M3 Chertsey Bridge to the north of Chertsey and then has its second junction, at the M25 motorway, before continuing through the gorse, bogs and heather of the Surrey Heath. Its third junction is for Camberley, Bagshot, Bracknell, Ascot and Worplesdon.
From Junction 4, the motorway bisects the northern Blackwater Valley conurbation and crosses the river into Hampshire. Soon afterwards comes Fleet and nearby early 21st century expanded/new villages such as Elvetham Heath. It skirts Old Basing and Basingstoke to its north. Turning south-west again, it passes the light aircraft at Popham Field and, just before reaching Junction 8, where one lane becomes the A303 road, and the motorway continues with just two a side through open countryside and Micheldever Wood until it reaches the north of Winchester.
Taking over the "Winchester Bypass" the M3 resumes to three lanes each way at Junction 9, continues directly south and then takes a small curve around the east of the city running through a deep cutting in Twyford Down and then proceeding south-west again alongside the River Itchen and through the Eastleigh suburban area and ending at the Chilworth Roundabout on the edge of Southampton.
- The Spitfire Bridge carries the B3404 Alresford Road to Winchester over the M3 motorway and the parallel A272 (J9-J10 spur). This is known as the "Spitfire Link". It replaced a concrete parabolic arch bridge under which a George Rogers flew a Curtiss P-40 'Warhawk' in October 1941. It was generally assumed locally that the aircraft had been a Spitfire, hence the name.
- A private exit of the northern roundabout connected to Junction 4a provides access to the UK headquarters of Sun Microsystems.
|M3 motorway junctions|
|miles||North-east bound exits (B carriageway)||Junction||South-west bound exits (A carriageway)|
|15.0||Road continues as A316 to London||J1||Sunbury, Kingston A308|
|15.3||Sunbury, Kingston A308||Start of motorway|
|21.3||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|
|28.1||Woking, Bracknell, Bagshot, Lightwater A322||J3||Woking, Bracknell, Bagshot, Lightwater A322|
|32.6||Guildford, Farnham, Camberley, Farnborough, Aldershot A331||J4||Guildford, Farnham, Camberley, Farnborough, Aldershot A331|
|34.4||Fleet (A3013), Farnborough (West) A327||J4a||Fleet (A3013), Farnborough (West) A327|
|Fleet services||Services||Fleet services|
|41.9||Hook A287 B3349||J5||Hook A287 B3349|
|46.6||Basingstoke, Reading (A33), Alton A339
||J6||Basingstoke, Newbury, Reading, Alton A339|
|51.8||Basingstoke A30||J7||Basingstoke A30|
|53.1||No access||J8||The South West, Andover, Salisbury A303|
|59.9||Winchester services||Services||Winchester services|
|63.9||The Midlands, Newbury A34
Winchester A272, Alresford A31
|J9||The Midlands, Newbury A34|
|65.2||Winchester (City) B3330
Alton, Alresford A31
|70.0||Eastleigh (North) A335||J12||Eastleigh (North), Chandler's Ford A335|
|71.8||Eastleigh, Chandler's Ford A335||J13||Eastleigh A335|
|Start of motorway||J14||Southampton , Portsmouth M27(E)|
The West, Southampton Docks, Bournemouth M27(W)
| ("Wikimedia Commons" has material|
about M3 motorway)
- "The M.3 Motorway". Hansard. 1967. http://hansard.millbanksystems.com/lords/1967/jun/21/the-m3-motorway.
- "The M.3 Motorway". Hansard. 1967. http://hansard.millbanksystems.com/lords/1967/jun/21/the-m3-motorway. Oral Questions in the House of Lords 21 June 1967 vol 283 cc1385-7
- "M3 London to Southampton Route Management Strategy". Department for Transport. http://www.highways.gov.uk/roads/projects/6363.aspx.
- "M3 (Sunbury-Popham)". Hansard. 1988. http://hansard.millbanksystems.com/written_answers/1988/jan/11/m3-sunbury-popham.
- "M3 London to Basingstoke Motorway: Popham to Compton public inquiry". National Archives. http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=8280346&CATLN=6&accessmethod=5.
- "M3. London to Southampton". The Motorway Archive. http://www.iht.org/motorway/m3londsouth.htm.
- Morgan Morgan-Giles (26 July 1976). "M3 MOTORWAY INQUIRY". Hansard. http://hansard.millbanksystems.com/commons/1976/jul/26/m3-motorway-inquiry. Retrieved 11 March 2013.
- "M3 London to Basingstoke motorway: Popham to Compton; public inquiry 1976". National Archives. http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=8530136&CATLN=6&accessmethod=5.
- "Annual Average Daily Traffic Flows". Department for Transport. http://www.dft.gov.uk/matrix/Default.aspx. Retrieved 28 September 2009.
- Myth of pilot's bridge stunt - Southern Daily Echo 31 October 2003
|Motorways in the United Kingdom|
Great Britain: M1 • M2 • M3 • M4 • M5 • M6 • M6 Toll • M8 • M9 • M10 • M11 • M18 • M20 • M23 • M25 • M26 • M27 • M32 • M40 • M42 • M45 • M48 • M49 • M50 • M53 • M54 • M55 • M56 • M57 • M58 • M60 • M61 • M62 • M63 • M65 • M66 • M67 • M69 • M73 • M74 • M77 • M80 • M85 • M90 • M180 • M181 • M271 • M275 • M602 • M606 • M621 • M876 • M898 • Sections of A road: A1(M)
Former motorways marked in italics