The driver of a car involved in a crash on the M4 that took the life of a woman from Oxford remains in serious condition in hospital.

The crash happened at around 11.50am on Saturday (March 9) as a Volvo S40 left the carriageway and collided with a tree.

Emergency services were called to the M4 westbound between junctions 15 and 16 but the front seat passenger, a woman in her 60s from Oxford, died at the scene.

READ MORE: Road to close for 'number of hours' for crash investigation works

There were three other people in the car and all sustained injuries from the crash.

Both the male driver and a female passenger aged in her 20s were taken to Southmead Hospital in a life threatening condition.  

Wiltshire Police have now confirmed that the female passenger is no longer fighting for her life, but the driver remains in a serious condition.

A male passenger aged in his 30s also sustained an arm injury during the incident.

The westbound carriageway remained closed for around 11 hours while investigation work was carried out but reopened shortly before 11pm on Saturday.

Det Con Leigh Mayhew from our Serious Collision Investigation Team, said: “This was a very serious collision in which a woman sadly lost her life and two other people were very seriously injured.

"It happened at a busy time of day on the M4 however, we have not been able to identify as many witnesses as we would expect.

"If you were travelling on the M4 on Saturday morning shortly before midday and you witnessed the collision which happened on the westbound carriageway approximately one mile from junction 16, please get in touch immediately.”

An air ambulance was also called to the scene along with police cars as the emergency services raced to the motorway.

The road closure led to long delays with traffic queuing on the westbound approach to junction 15.

A spokesperson for Wiltshire Police initially said: “We were called at 11.50am this morning to a report of a collision on the M4 westbound between junctions 15 and 16.

“One vehicle left the carriageway and collided with a tree.

“Four people have been injured and the westbound carriageway has been closed while the incident is dealt with.”

Anyone who witnessed the collision or anyone who may have dash cam are asked to contact the Serious Collision Investigation team on 01225 694597 quoting log number 127. Alternatively, email SCIT@wiltshire.police.uk.