The incident took place shortly before midday between J19 for Bristol and J20 for the Almondsbury Interchange. Motorists can expect up to four miles of congestion and delays of around half an hour to their journeys.

Highways England tweeted: “#M4 J19 Bristol to J20 #AlmondsburyInterchange westbound – We currently have two lanes closed due to an accident, as a result there is congestion in the area.

“Please follow all signs and signals.”

It added: “There are long delays on the #M4 J19 (#M32) to J20 (#M5) due to this collision.

“There are currently 4 miles of congestion which is likely to add around 30 minutes to normal journey times.”

This is a developing news story, more to follow.