"We are appealing for witnesses following a fatal collision on the M4 involving two vehicles between junctions 16 and 17.

"The incident happened just before 11.30pm last night (22/06).

"A female in her 40s sadly died at the scene. Another female aged in her 70s was seriously injured, and five other people sustained minor injuries. There were three people travelling in the second car. They also sustained minor injuries. All nine people have been taken to hospital for treatment.

"Our Serious Collision Team are at the scene carrying out an investigation into what happened, and the motorway is likely to be closed westbound for most of the day. We appreciate this will cause disruption for a large number of people and thank you for your patience.

"We have received reports that a white vehicle may have been involved and left the scene.

"Any witnesses to the collision or anyone who may have dashcam footage are asked to contact the serious collision investigation team on 01225 694597, quoting log number 399.

"Alternatively, contact the team directly by emailing SCIT@wiltshire.police.uk"