The M4 in Greater London is closed westbound between J1 Chiswick Roundabout and J3 Cranford Parkway Interchange (Heathrow Airport T4 & Cargo, Feltham, Hayes A312). This is due to a multi-vehicle collision. Metropolitan Police. London Fire Brigade, London Ambulance Service and National Highways have units attending. A diversion is available: Exit the A4 at J1 of the M4 (Chiswick Roundabout) and join the A4 Great West Road Continue on to the A4 Bath Road At the roundabout with the A312 The Parkway take the third exit Head north on the A312 The Parkway to J3 of the M4 At the junction roundabout take the second exit to re-join the M4 westbound. Road users intending on travelling on this section of the A4 are advised to allow additional time for their journeys. If possible please consider alternate routes.