THERE has been a "serious collision" between J29 Castleton and J32 Coryton that has closed the M4 Westbound.

The Eastbound is still open, but Traffic Wales South says to expect delays.

The M4 Eastbound carriageway will now be closed between J33 Capel Llanilltern and J32 Coryton because of an Air Ambulance landing at the scene.

Drivers are advised to avoid the area if possible.

Update: One lane has been reopened on the M4 Eastbound J33 Capel Llanilltern and J32 Coryton.

A spokesman from South Wales Police said: "South Wales Police is in attendance at a road traffic collision on the M4.

"The road is closed in both directions between Junction 30 and 32.

"Motorists are advised to take an alternative route".

A spokeswoman for Wales Air Ambulance Charity said: "“We can confirm the Wales Air Ambulance Charity helicopter attended an incident on the M4 between junctions 32 to 33 this morning.  

"Our Dafen crew was mobile at 11.16am and arrived on scene at 11.40am. Following treatment at the scene, our medics escorted the patient via road ambulance to the University Hospital of Wales, Cardiff.

"Our involvement concluded at 12.55pm".