All traffic has stopped on the M25 anti-clockwise near Heathrow Airport due to a “serious” two-car crash.
The motorway has shut between junction 17 in Rickmansworth and junction 16 since 2.30pm today (June 24).
National Highways (@HighwaysEAST) is urging motorists on X (formally known as Twitter) to consider alternative routes where possible.
There are currently seven miles of congestion on approach which is causing 90-minute delays.
It is unknown when all traffic restrictions will be lifted.
We have contacted Thames Valley Police and South East Coast Ambulance Service for further information.
A spokesperson for National Highways said: “The M25 in Buckinghamshire is closed anti-clockwise between J17 (Rickmansworth) and J16 (M40) due to a serious collision.
“Emergency services are in attendance.
“National Highways Traffic Officers are also on scene to assist with traffic management.”
The full statement from AA maps says: “Severe delays and three lanes closed due to crash, two cars involved on M25 anticlockwise before J16 M40 J1A.
“Congestion to J19 (Watford), with the opposite side back to J14 (Heathrow Terminal 4) due to onlookers.”