A police officer who suffered neurological injuries after crashing on the M90 is still unconscious and receiving intensive care in hospital.

The policeman and his colleague were responding to reports of a drink-driver when they left the road and crashed onto a grass verge on Sunday night at around 9.40pm.

Both were seriously injured.

The driver of the marked BMW 330 patrol car had to be removed from the vehicle by firefighters and was taken to the Western General Hospital in Edinburgh, where family remain by his bedside.

His passenger was taken to Ninewells Hospital in Dundee with back injuries.

Chief superintendent Stewart Carle, who earlier thanked the passing motorists and 999 responders who gave treatment, visited the unconscious officer on Thursday night with chief inspector Mark Patterson.

Posting on Twitter, he said: "Today with CI Patterson, I visited one of Road Policing Scotland's officers injured in Sunday evening's RTC on M90.

"Whilst he remains unconscious, the intensive treatment and care from NHS Scotland is humbling as is the bravely optimistic love and unstinting attention from his fiancee and family."

Following the single-vehicle crash, the M90 remained closed overnight between J4 Kelty in Fife and J5 Gairneybridge in Perth and Kinross while a full investigation took place.

The road eventually reopened at 9.20am on Monday.

Chief inspector Mark Patterson, from Road Policing East, said: "The officers in the patrol car were responding to the report of a drunk driver on the motorway when the collision happened.

"Our thoughts are with both officers and their families at this time.

"I would appeal to anyone who may have witnessed this collision to call Police Scotland on the 101 number."