A 21-year-old thug responsible for killing another man after hitting him with one punch has been jailed for four-and-a-half years.

Nowbahar Bahar claimed he was acting in self-defence when he struck David Henkel, but a jury at Maidstone Crown Court convicted him of manslaughter.

The court heard that Bahar, of Harmer Street, Gravesend, was an "overstayer" in this country.

He arrived from Afghanistan in August 2001 and was given permission to stay for four years. He has now been served with deportation papers.

Mr Henkel, who was 32 and lived in Luton Road, Chatham, with his girlfriend Leanne O’Brien, died following an argument with Bahar over money for drugs.

David Jeremy, prosecuting, said the couple had been out for the evening in the town with a friend on July 23 last year.

They visited several pubs and had several pints. They eventually left one pub to buy more alcohol from an off-licence to take home.

It was then that he met Bahar. Also present were two 15-year-old girls, who became the chief witnesses.

They told police that Mr Henkel approached Bahar in Bank Street, Luton, Chatham and asked him if he knew of an off-licence that would be open and where he could get some skunk cannabis.

Bahar took £10 from Mr Henkel and went off. He returned after a short while and told Mr Henkel he had lost his money.

"Not surprisingly, Mr Henkel became annoyed," said the prosecutor. "They argued. There was some pushing. The defendant took the argument one stage further by punching Mr Henkel in the face.

"It was a hard punch. It knocked him straight to the ground, causing him to hit his head either against a wall or on the ground. It was a position from which Mr Henkel was never to get up."

He was taken to the Medway Maritime Hospital, where he never regained consciousness. He was certified dead the next day.

Mr Jeremy said a post mortem examination showed that Mr Henkel died from a fracture of the skull as he fell.

Bahar claimed that Mr Henkel had hit him first and he had given him one "soft" punch in return. But the two teenage witnesses said Bahar threw the only punch.

Mr Jeremy said Bahar had 17 previous convictions for offences including theft, threatening behaviour and criminal damage. He is awaiting sentence for theft.

Judge Andrew Patience, QC, told Bahar he had committed a grave offence. "No value can be put upon a life which has been lost," he said. "Nothing I can say can lessen the sense of grief and loss which his friends and family feel and nothing I can say can bring him back."

The judge said he dealt with Bahar on the basis that he did not intend to cause the victim serious harm, let alone his death.

"You could not have anticipated that these terrible consequences could result from you punching him as hard as you did," he said.

"I have no doubt it was a hard blow, causing him to be lifted off the ground before he fell on the hard road."