The M4 motorway is a motorway in the UK, which goes west from London past Bristol to Wales

Westbound

  • The M4 starts six miles west of central London where the A4 merges into the M4 on a raised flyover. (The A4 continues in its own right below the flyover.)
  • Junction 1 (restricted access): A205 South Circular, A406 North Circular, A315 Chiswick, A4.
  • Junction 2: A4 Staines, Hounslow.
  • Heston services.
  • Junction 3: A312 Heathrow Airport Terminal 4 and cargo, Hayes, Harrow, Feltham.
  • Junction 4: M4 spur Heathrow Airport terminals 1, 2 & 3, A408 Uxbridge. Access via spur to Junction 4a and A4 east and west.
  • Junction 4b: M25 Heathrow Airport Terminal 4 and cargo, Gatwick Airport, Watford, Oxford.
  • Junction 5: A4 Colnbrook, Langley, B470 Dachet.
  • Junction 6: A355 Slough central, A332 Windsor.
  • Junction 7: A4 Slough west.
  • Junction 8/9: A404M High Wycombe, Henley, A308M Maidenhead.
  • Junction 10: A329M Reading east, Wokingham, Bracknell.
  • Junction 11: A33 Basingstoke, Reading central and south.
  • Reading services.
  • Junction 12: A4 Theale, Reading west.
  • Junction 13: A34 Newbury, Oxford, Chieveley services.
  • Junction 14: A338 Hungerford, Wantage.
  • Membury services.
  • Junction 15: A346 Marlborough, A419 Swindon, Gloucester.
  • Junction 16: A3102 Swindon west, Wootton Bassett, Calne.
  • Junction 17: A350 Chippenham, A429 Cirencester.
  • Leigh Delamere services.
  • Junction 18: A46 Bath, Stroud.
  • Junction 19: M32 Bristol.
  • Junction 20: M5 The south west, Bristol west, The midlands, Gloucester.
  • Junction 21: M48 Chepstow This is the old M4
  • Junction 22: M49 Avonmouth.
  • Second Severn Crossing (bridge).
  • Junction 23: No exit
  • Junction 23a: Magor services. B4245 Magor, Caldicot.
  • Junction 24: A455/A48 Newport east, A449 Monmouth.
  • Junction 25: B4596 Caerleon.
  • Junction 25a: A4042 Newport, Cwmbran.
  • Junction 26: A4051 Newport.
  • Junction 27: B4591 High Cross.
  • Junction 28: A48 Newport, A467 Risca, Brynmawr.
  • Junction 29: A48(M) Cardiff east and south.
  • Junction 30: A4232 Cardiff east.
  • There is no Junction 31
  • Junction 32: A470 Cardiff north, Merthyr Tydfil.
  • Junction 33: Cardiff West services. A4232 Cardiff west, Barry, Penarth, airport.
  • Junction 34: A4119 Llantrisant, Rhondda.
  • Junction 35: A473 Bridgend, Pen-coed.
  • Junction 36: Sarn Park services. A4061 Bridgend, A4063 Maesteg.
  • Junction 37: A4229 Porthcawl, Pyle.
  • Junction 38: A48 Port Talbot.
  • There is no Junction 39
  • Junction 40: A4107 Port Talbot.
  • Junction 41: A48 Briton Ferry.
  • Junction 42: A483 Swansea and ferry.
  • Junction 43: A465 Neath, Merthyr Tydfil.
  • Junction 44: A48 Swansea east.
  • Junction 45: A4067 Swansea, Pontardawe.
  • Junction 46: B4489 Swansea north.
  • Junction 47: Swansea West services. A483 Swansea west.
  • Junction 48: A4138 Pontarddulais, Llanelli.
  • Junction 49: End of motorway. Pont Abraham services. A48 Carmarthen, Pontarddulais, A483 Llandeilo.

Eastbound

See also List of motorways in the United Kingdom