DIESEL spilling from an overturned milk tanker is causing delays on the M4 following a crash this morning. 

The tanker crashed at around 6.20am, blocking all three lanes between junctions 17 and 18.

Highways England have told drivers to expect delays on the motorway and is putting in diversions after diesel poured over the road.

It has said the motorway will remain closed for emergency resurfacing due to the spill.

Traffic is being diverted at junction 17 towards Chippenam and onto the A350 and A46 to rejoin the M4.

No casualties have been reporterd from the crash.