Police have blamed poor mobile phone reception for a drink-driver escaping justice.

The force said a call they received about the driver kept breaking up and they had insufficient information to nab the offender.

Photographer Mark Dimmock alerted police after spotting the man slumped in his stationary Mercedes in the middle of a narrow lane.

He waited an hour but police failed to show before the driver sped away, swerving.

Mr Dimmock, who was with his wife and two young children in his car, said: "So much for police asking people to shop drink drivers.

"He was at the wheel of a lethal weapon and I just hope he didn't injure someone or worse."

Police said Mr Dimmock's mobile call broke up and they were not sure exactly where the driver was.

They also had the impression the Mercedes was on the move.

Chief Superintendent Wayne Jones, head of communications for Sussex Police, praised Mr Dimmock for his public spirited action and said he was sorry police were not able to interview the suspect driver.

However, he urged people to continue calling in with information about drink drivers.

Mr Dimmock, from Eastbourne, was driving between Alfriston and Litlington on Wednesday afternoon when he had to stop behind the Mercedes.

He said: "The driver's head was hanging out of the window and there were boxes lying in the road.

"I went to see if he was okay. I shook him and there was an overpowering stink of booze. He was quite aggressive and I backed off."

When police failed to turn up after 50 minutes, Mr Dimmock called again, this time from a telephone kiosk. Ten minutes later, the driver sped away.

Mr Dimmock said: "I was dis-appointed. We're supposed to shop drink drivers but if police don't turn up, what is the point?"

Mr Jones said mobile phone reception and transmission in the Alfriston area was poor.

He said: "All we had were snatched pieces of conversation and we did not know the location or that the Mercedes was stationary.

"The operator tried to call Mr Dimmock back on his mobile but we could not get through. By the time the second call came through it was too late."

Mr Jones said police were able to discover the owner's identity thanks to Mr Dimmock taking the registration number of the Mercedes.

He said: "We will pass the information to the police where he lives.

"It is too late to take any action against him now but police in his home town are now aware and they will be keeping an eye on him.

"Mr Dimmock acted quite properly and we want to thank him."