Police are appealing for witnesses after a motorcyclist was killed in an accident on the A4074.

The crash - between the Golden Balls roundabout and the Berinsfield roundabout - occurred shortly before 9.45am.

An ambulance and helicopter carrying a doctor were scrambled, but the motorcyclist, a 40-year-old man who has not yet been formally identified, was pronounced dead at the scene.

The road was closed in both directions and traffic diverted until 1.30pm while police carried out investigations.

The coroner and the man's family have been informed of his death.

Both the motorcyclist and the driver of the Ford Transit van had been travelling southbound along the road, which links Oxford and Reading, when the collision occurred.

Accident investigator Sgt Sarah Flavin said: "We are aware there were several motorists who may have seen the collision and not stopped and spoken to police.

"I would like to speak to anyone who may have seen the collision, or the motorcyclist or van before- hand."

The man's red motorcycle was removed from the scene by a recovery truck team shortly before 1pm.

Speaking at the scene, Pc Jude Miranda, of Abingdon Police Station, said: "The motorbike was in bits, the lights and the number plates were found about 15 or 20 feet away.

"The body was found in the layby along with the motorbike."

Phil Warwick, 41, a supervisor from Oxfordshire Highways, who was at the scene diverting traffic, said the driver of the van was a colleague.

He said: "He was pretty shaken up. He said he just came off the Golden Balls roundabout heading south and was trying to turn right when it happened."

The collision happened just yards from a sign reminding motorists about the number of accidents which have happened on the notorious stretch of road.

In April, 22-year-old motorcyclist Mark d'Ardenne died in a head-on collision further south on the A4074, on the Dorchester bypass.

Anyone who witnessed yesterday's collision and is yet to speak to Thames Valley Police should call Sgt Flavin on 08458 505505.