Police have criticised drivers after two people died and dozens were injured, some seriously, after a series of accidents on the fog-bound M40.

More than 100 vehicles were involved in numerous collisions on the motorway yesterday morning.

Pc Andy Rowley, of Thames Valley Police, said the pile-up was probably caused by drivers travelling too fast in treacherous conditions.

He said: "The road was very foggy and we had one accident involving two vehicles.

"As traffic began to slow, we had numerous vehicles plough into the vehicles in front of them.

"The one conclusion that can be drawn is that people were driving too fast in the fog and not leaving enough room between them and the vehicles in front. That will be a major factor in our investigation."

Police closed the London-bound carriageway and three hours after the initial accident, 20,000 vehicles were at a standstill in a 15-mile tailback towards Banbury.

Police were alerted shortly after 7am when a motorcycle and a van collided on the motorway near Lewknor. The motorcyclist died. A second man died later in the John Radcliffe Hospital, Oxford. Neither man has been named.

Twelve casualties were taken to the John Radcliffe Hospital, Oxford, two by helicopter and the rest by ambulance.

One was said to be in a critical condition and several others were being treated for serious injuries. Four other casualties were taken to High Wycombe Hospital, one of whom was detained.

Thames Valley Police set up an emergency helpline for people concerned that their friends and relatives could be involved in the pile-up. The number is 08459 441 551. The John Radcliffe Hospital also has a helpline 01865 222 188.