M4 chaos: Police launch investigation into crash near Heathrow Airport as drivers face miles of traffic

All emergency services are in attendance at the accident, including the Metropolitan Police and the London Ambulance Service.

National Highways has also confirmed that its traffic officers are in attendance to assist with the management of the congestion.

The transport organisation warned that collision investigations are expected to take several hours and will be protracted.

There is currently no estimated time of when the carriageway will reopen, although drivers are facing at least 90 minutes of delays.

Motorists are also facing five miles of heavy congestion between Junction 2 and the closure at Junction 3.

Traffic cameras show long columns of stationary vehicles as the aftermath of the accident continues to have an impact on travellers.

Road users are advised to follow the route marked with a hollow diamond symbol on local road signs

M4 westbound traffic:

• At junction 3, exit the M4 and take the 3rd exit onto the A312, The Parkway
• Continue following the A312 (The Parkway) through three roundabouts for approximately 4.1 miles
• At the fourth roundabout, take the second exit and continue on the A312 Church Road
• At the next roundabout, take the 1st exit and join the A40 westbound
• Continue on the A40 as it merges into the M40
• At J1A, exit the M40 to access the M25 anti-clockwise from J16 to J15
• Follow the M25 anti-clockwise to J15 and exit at J15 to access J4B M4

Heathrow T1-5 traffic:

• At J3, exit the M4 and take the 1st exit onto the A312 The Parkway
• At Waggoner's roundabout, take the 3rd exit onto the A4 Bath Road
• At the A408/Nene Road, turn left and exit the A4
• At the next roundabout, take the 3rd exit onto East Ramp, and the next roundabout is the Heathrow Tunnel roundabout

Posting on social media site X, formerly known as Twitter, Heathrow Airport warned: "The M4 westbound is closed between Junction 3 (Feltham) and Junction 4B (Heathrow) following an overnight road traffic incident.

"Diversions are in place, passengers are advised to allow extra time for their journeys to and from Heathrow and consult www.trafficengland.com for the latest information."

It comes after Heathrow Airport issued a further warning to travellers that the Piccadilly line is closed today due to industrial action, causing additional concerns for people visiting the airport.

Rail replacement buses will replace the Piccadilly line today, while other services, including the Heathrow Express and bus services, will operate as normal.