What caused a 22-year-old Fishguard man to lose control of his car and crash into a field, clearing a roadside hedge, remains a mystery, an inquest decided on Thursday.

Before recording a verdict that Dean Thomas Brock of 19, Garn Fawr, Maeshyfryd, died from multiple injuries caused when he lost control of his car, which collided with a hedge and crossed over into an adjacent field, Pembrokeshire Coroner Michael Howells said: "Tests show he was not behaving irresponsibly that night and I hear he was a sensible driver."

He added that there was no evidence of drink or drugs.

Dean died after his car left the A407 near the Keeston junction as he drove towards Haverfordwest from Newgale at 3.04am on Saturday May 17th.

Coroner's Officer Jeremy Davies said he had been with friends at a campsite at Newgale. Rebecca Joel from Merlins Bridge said that Dean left before her but she managed to catch his car up at Simpson Cross.

She had been travelling at 60mph and when she caught him he put his foot down and went out of sight.

Elise O'Neill, a passenger in Miss Joel's car, said it was a wet night and they were asked to leave the campsite.

Dean had Jason Smith and Sarah Sutton in his car, and, after he accelerated away from them, she did not see his car again.

When he failed to turn up in Fishguard she rang his mobile number but got no reply, and then the police rang to say there had been an accident.

Thomas Griffiths of Hill Mountain, Burton, gave evidence that he was sleeping in a tent on a scout camp in a friend's garden when he was awakened about 3am by a loud bump.

He did not associate it with an accident and thought that groaning noises were sheep in the field. But when he shone his torch he saw the rear number plate of a car and found Jason Smith lying groaning outside the car and Sarah Sutton bent double in the passenger seat.

Two men in a passing car, which hit debris in the road, stopped to investigate and found Dean lying dead 10 metres from the car.

Police Collision Investigator PC Michael John, said the car was very badly damaged having collided with the offside verge and vaulted the hedge into the field below. It must have become inverted before landing on its wheels and Dean and Jason were thrown out.

The accident happened at about 3.04am and the car ended up 60 metres across the field. Neither passenger could remember anything.

There were no defects which could have caused the accident, said PC John, who added: "We can offer no explanation why the vehicle went to the offside and over the hedge."

Said the Coroner: "This is one of those mysterious road accidents where nobody can give me any evidence as to how it actually happened."

There was no evidence that he had been travelling at high speed as the following car caught up with him.