The cause of a crash that closed the M4 near Swindon on Wednesday morning has been revealed.

Both the eastbound and westbound carriageways were shut between Junctions 16 and 17 at around 5.20am on February 14 after a vehicle left the road.

The eastbound side reopened at around 6.45am and most of the westbound side reopened at 7.30am, with one lane remaining closed until around 8.30am so that the vehicle could be safely recovered.

Police cars and fire engines attended the scene of the emergency.

A Dorset and Wiltshire Fire and Rescue Service spokeswoman said: "We were called to the M4 westbound between J16 and J17 at 5.55am this morning to assist the police.

"Three crews attended, from Swindon, Royal Wootton Bassett, and Westlea.

"High-pressure air mats were used to lift a vehicle that had left the carriageway and was on its roof down the embankment.

"This was to allow a search of the vehicle for the driver, who was not located.

"Our stop was at 7.31am."

The westbound closure caused miles of tailbacks up to Junction 15, with diverted traffic causing further congestion near Royal Wootton Bassett.

A Wiltshire Police spokesperson said: "We received a report shortly before 4.30am this morning to a report that a vehicle had left the M4  and gone in to a ditch between junction 16 and 17.

"Two lanes of the M4 were closed while enquiries were carried out to locate the vehicle."