POLICE were this morning continuing to investigate a crash which saw a van flip over, leaving a man critically injured.

The accident on the M3 left the northbound carriageway closed for 12 hours as recovery work and investigations into the cause of the incident took place.

Last night Hampshire police said the man remained in a critical condition in hospital.

Officers are now asking for help from the public to pinpoint the cause of the collision, which happened just after 7pm on Friday.

It is thought that the white Ford Transit van left the road and hit a mile marker post.

What caused the driver to veer into the marker post is now at the centre of the inquiry.

The man was flown to Southampton General Hospital for treatment after all emergency services were called to the scene between junctions 7 and 6 at Basingstoke.

Hampshire Constabulary says the man, who is from Bournemouth, suffered a severe leg injury.

South Central Ambulance Service deployed a rapid response vehicle, an ambulance crew, and a Hazardous Area Response Team. The Thames Valley Air Ambulance was also scrambled.

A spokeswoman from SCAS said crews treated one man at the scene for serious, multiple injuries before he was flown to Southampton General Hospital for further treatment.

Hampshire police thanked the public for their patience whilst they carried out investigations at the scene of the accident and confirmed the northbound carriageway had reopened yesterday.

The hard shoulder of the motorway remained closed for much of yesterday.