The M4 is the main road running between London and South Wales, passing Slough, Reading, Swindon, Bristol, Newport, Cardiff and Swansea along the way. Like the rest of the UK road network, the M4 has areas where tailback is most likely – mainly where it joins M25 on the west side of London and also where it meets M5 near Bristol. Naturally, accidents, road work and other traffic problems cause delays, so you should take care of your journey before starting the engine.
There used to be a road toll over the M4 Severn bridge connecting England and Wales, but after 52 years, the toll was abolished on 17 December 2018.
In general, the M4 tends to be relatively clear for the most part, but the 189-mile route can experience additional congestion during peak hours and summer holidays. If you plan to use any portion of the M4 motorway, this page will be a handy aid to travel warnings, live updates and trouble maps for both westbound and outbound lanes. Winter.
Tweets
Scroll down to find live tweets about the latest traffic conditions on the M4.
Live highway camera M4
If there is a traffic disruption on the M4, you can update any delays with a live traffic camera for east and West M4.
M4 . weather report
Details of the latest weather warnings in the M5 area from the Met Office…
• Met Office Southwest Weather Report
History of M4
The Department for Transport first proposed a new road from London to South Wales in the 1930s. Plans for the M4 as one of the first major post-war arterials were made in 1956 and began Construction began in 1961. The Chiswick Overpass, a short section of elevated two-way street built to reduce the impact of traffic between central London and the west, opened in 1959 and later became part of the new M4 route. The section from J18 to the west side of Newport opened in 1966, including the Severn Bridge, now part of the M48.
The English section of the highway was completed in December 1971 when the 50-mile stretch between Maidenhead and Swindon was put into public use. The Welsh section was completed in 1993, when the Briton Ferry bridge opened to traffic. The second Severn intersection opened in 1996, and motorways on either side of the river brought the M4 over the new overpass when construction was finally completed.
• Traffic M5: live news updates
M4 . intersection points
All M4 crossings on southbound and northbound routes are detailed below…
Exit to the east (B street) |
Junction |
West Exit (Horse Road) |
The road continues like A4 arrive Central London |
J1 |
Start of the highway |
Northern Roundabout A406
Male circle A205
Chiswick A315
|
J2 |
Staines, Hounslow, Brentford A4 |
Heston Service |
Service |
Heston Service |
Heathrow (Terminal 4, 5 & Goods), Hayes, harrow, Hounslow A312 |
J3 |
Heathrow (Terminal 4, 5 & Cargo), Hayes, Harrow, Hounslow A312 |
Heathrow (Terminals 1, 2 & 3) (A4)
Uxbridge A408
|
J4a |
Heathrow (Terminal first2 & 3) (A4)
Uxbridge A408
|
Heathrow (Terminal 4, 5 & Goods), Gatwick Airport , Watford (M3), (M23), (M40), (M1) M25 |
J4b |
Heathrow (Terminal 4, 5 & Cargo), Gatwick, Watford (M3), (M23), (M40), (M1), M25 |
Colnbrook, Langley, Slough (East) A4
Eton, Datchet B470
|
J5 |
Colnbrook, Langley, Slough (East) A4, Datchet B470 |
Slough (Central) A355
Windsor A322
|
J6 |
Slough (Central) A355
Windsor A322
|
Slough (West) A4 |
J7 |
Slough (West) A4 |
High Wycombe, Henley A404 (M)
Maidenhead A308 (M)
|
J8 / 9 |
High Wycombe, Henley A404 (M)
Maidenhead A308 (M)
|
Read (East), Wokingham, Bracknell A329 (M) |
J10 |
Read (East), Wokingham, Bracknell A329 (M) |
Basingstoke, Read (Central & Southern) A33 |
J11 |
Basingstoke, Read (Central & Southern) A33 |
Reading service |
Service |
Reading service |
Read (West), Theale A4 |
J12 |
Read (West), Theale A4 |
Newbury, Oxford A34
Chieveley Service (Moto)
|
J13
Service
|
Newbury, Oxford A34
Chieveley Service (Moto)
|
Hungerford, Wanted A338 |
J14 |
Hungerford, Wanted A338 |
Membury’s Service |
Service |
Membury’s Service |
Swindon (East) A419
Marlborough A346
Oxford (A420)
|
J15 |
Swindon A419, Marlborough A346 |
Swindon (West), Royal Wootton Bassett, Wroughton, RAF Lyneham, Calne A3102 |
J16 |
Swindon (West), Royal Wootton Bassett, Wroughton, RAF Lyneham, Calne A3102 |
Chippenham A350
Cirencester A429
|
J17 |
Chippenham A350
Cirencester A429
|
Service Leigh Delamere |
Service |
Service Leigh Delamere |
Bathtub, Stroud A46 |
J18 |
Bathtub, Stroud A46 |
Bristol M32 |
J19 |
Bristol M32 |
Southwest, Bristol (West), Midland, Gloucester M5 |
J20
Almondsbury Crossing
|
SOUTH WEST, Bristol (West) M5 (S)
MIDLANDS, Gloucester M5 (N)
|
Inaccessible |
J21 |
Chepstow M48 |
Avonmouth M49 |
J22 |
Avonmouth M49 |
Entry to the UK |
Second Severn Crossing |
Entry to Wales |
There is no toll station |
Toll bridge |
Toll plaza |
Chepstow M48 |
J23 |
Inaccessible |
Magor, Caldicot A4810
Magor Service
|
J23A
Service
|
Magor, Caldicot A4810
Magor Service
|
Downtown A48
Newport (East) B4237
Monmouth A449
Midland (M50)
|
J24 |
Downtown A48
Newport (East) B4237
Monmouth A449
|
Inaccessible |
J25 |
Caerleon B4596 |
Inaccessible |
J25A |
Newport, Cwmbran A4042 |
Brynglas . Tunnels |
Tunnel |
Brynglas . Tunnels |
Newport, Cwmbran, Caerleon A4051 |
J26 |
Newport A4051 |
High cross B4591 |
J27 |
High cross B4591 |
Newport A48
Risca, Brynmawr A467
|
J28 |
Newport A48
Risca, Brynmawr A467
|
Inaccessible |
J29 |
Cardiff (East and South) A48 (M) |
Cardiff (East) A4232
Cardiff Gate Service
|
J30
Service
|
Cardiff (East) A4232
Cardiff Gate Service
|
Merthyr Tydfil, Cardiff A470 |
J32 |
Cardiff (North), Merthyr Tydfil A470 |
Cardiff (West), Barry, Penarth A4232
Cardiff Airport
Services of Cardiff West
|
J33
Service
|
Cardiff (West), Barry, Penarth A4232
Cardiff Airport
Services of Cardiff West
|
Llantrisant, Rhonda A4119
Royal Glamorgan Hospital
|
J34 |
Llantrisant, Rhonda A4119
Royal Glamorgan Hospital
|
Pen-coed A473 |
J35 |
Bridgend, Pen-coed A473 |
Bridgend A4061
Maesteg A4063
Princess of Wales Hospital
Services of Sarn . Park
|
J36
Service
|
Bridgend A4061
Maesteg A4063
Princess of Wales Hospital
Services of Sarn . Park
|
Pyle, Porthcawl A4229 |
J37 |
Porthcawl, Pyle A4229 |
Port Talbot A48 |
J38 |
Port Talbot A48 |
No access (on ramp only) |
J39 |
Inaccessible |
Port Talbot A4107 |
J40 |
Port Talbot A4107 |
Port Talbot A48 |
J41 |
Briton Ferry A48 |
Briton Ferry A48
Swansea (South) A483
|
J42 |
Swansea (South) A483 |
Neath, Merthyr Tydfil A465 |
J43 |
Neath, Merthyr Tydfil A465 |
Swansea (East) A48 |
J44 |
Swansea (East) A48 |
Pontardawew, Swansea (North) A4067 |
J45 |
Pontardawew, Swansea (North) A4067 |
Llangyfelach B4489
Felindre
Morriston Hospital
|
J46 |
Llangyfelach B4489
Felindre
Morriston Hospital
|
Swansea (West) A483
Gorseinon A48
Swansea Service
|
J47
Service
|
Swansea (West) A483
Gorseinon A48
Swansea Service
|
Pontarddulais, Llanelli A4138 |
J48 |
Pontarddulais, Llanelli A4138 |
Start of the highway |
J49
Last station
Service
|
The highway ends at a roundabout:
Carmarthen A48
Ammanford, Llandeilo A483
Pontarddulais A48
Pont Abraham service
|