UPDATED: Forty vehicles involved in fatal M40 accident
Emergency services were called to the scene between Junctions 9 and 10 at around 7.50am to reports of a multiple collision on the northbound carriageway.
Thames Valley Police have confirmed one person died at the scene, one sustained life-threatening injuries, six people were seriously injured and approximately 35 to 45 people have minor injuries.
Inspector Daren Courtenay, from the Joint Operations Unit for Roads Policing said: “Officers are currently on the scene attending the ongoing incident.
“The northbound carriageway is currently closed and is expected to remain closed for a number of hours. The southbound carriageway is open, however restrictions are in place so delays should be expected.
“I would request drivers find an alternative route and would like to advise motorists to take extra care as there is fog in the area.”
Ambulance, fire, police and a hazardous area response team are all in attendance at the scene.