Dorset Police said the telephone caller caused the family to drive from their home in Witney, Oxfordshire, to the Dorset County Hospital in Dorchester, where they discovered the news was false.

Detective Inspector Mick Rand said: "This has been a terrible ordeal for the couple who have no idea as to who made the call, where it came from or indeed why it was made.

"The hoax caller used the false name of a Dr Thomas or a Dr Stevens and he sounded relaxed and convincing."

This was a despicable hoax call that caused the couple a lot of stress, worry and anxiety Detective Inspector Mick Rand

The couple said they believed the bogus caller because he called them at about 0530 BST on Monday claiming to be a doctor at the neurological department of the hospital.

He told them their son had been involved in a road traffic collision after an evening out at a Dorchester night club.

The caller also went into details about their son's injuries.

"The caller told the couple that their son was being treated for brain injuries and that his girlfriend had died," Detective Inspector Rand said.

'Sick joke'

"When the couple arrived at the Dorset County Hospital in Dorchester, they found out that the hospital doesn't have a neurological unit.

"The phone call had been a sick joke. Their son and his girlfriend had not been involved in a road traffic collision and were, in fact, safe and well.

"This was a despicable hoax call that caused the couple a lot of stress, worry and anxiety after they drove from down to Dorset thinking that their son was seriously injured and his girlfriend dead," he said.

Mr Rand said genuine callers from hospitals will always give their identity, department and telephone number and that hospitals never mind checks being made to ensure that phone calls are genuine.