An Oxford woman was pronounced dead at the scene following a horror crash on the M4 this weekend.

The collision occurred at around 11.50am on Saturday morning 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.

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.

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.

A spokesperson for Wiltshire Police said: “Specialist trained officers are supporting the next of kin of those involved and our thoughts are with them at this difficult time.

“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.”

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.

There had also been congestion on the eastbound carriageway, caused by roadworks, but this has now eased.

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.”

National Highways advised people to avoid the M4 in Wiltshire if they could until the road was fully reopened.

A spokesperson for National Highways at the time said: “The westbound carriageway in this area is expected to remain closed for some time as an investigation is carried out. 

“Motorists are strongly advised to allow extra time to travel, or even delay their journeys if at all possible.

“Further information and updates are available at www.trafficengland.com and travel apps, or via the @HighwaysSWEST 'X' (Twitter) feed.

“Our 24/7 contact centre team is also available to provide up to the minute information on 0300 123 5000.”