A PENSIONER sustained life threatening injuries in a two car collision that closed the M4 motorway yesterday afternoon.

A 36-year-old man was also injured in the crash and Thames Valley Police have since launched an investigation into what happened.

The collision involved a Mercedes van and a Ford Ka and took place around 2.30pm yesterday near Reading services on the westbound carriageway.

Officers closed part of the motorway between junction 11 for Reading and junction 12 for Theale to allow an air ambulance to land in the road.

It was later reopened at around 5.15pm and led to heavy traffic delays.

The 69-year-old woman, who was driving the Ford, was taken to the John Radcliffe Hospital in Oxford, with life threatening injuries.

She remains there in a critical condition.

The driver of the van sustained minor injuries in the collision.

Investigating officer PC Dave Beeson, from the serious collision investigation unit, said: “I would like to speak to anyone who witnessed the incident.

“If you have not already spoken to officers please do so as soon as possible as you may have information which could assist the ongoing investigation.”

Anyone with information about the incident should call the 24-hour Thames Valley Police enquiry centre on 101 quoting URN 760 22/4.

A spokesman for South Central Ambulance Service said: "We were called at 2.31pm to the M4 to a multi-vehicle road traffic collision.

"We sent and ambulance crew, two rapid response vehicles and ambulance officer and the Thames Valley Air Ambulance.

"They were assessing and treating a female in her seventies who suffered serious injuries as a result of the incident.

"She has been taken by land ambulance to the John Radcliffe Hospital."