The family of an electrician left brain damaged by an unexplained attack eight years ago – which eventually led to his death – issued a heartfelt plea for information this week.

Gerard Allison, of Pine Street, Clerkenwell, was found shirtless and unconscious in the street in Keystone Crescent, King’s Cross, by a child walking to school at 7.30am on the morning of Wednesday, August 11, 2004.

He had been beaten so badly that he was left severely brain damaged and needing constant care until his death.

Police never traced any witnesses and for eight years the brutal attack has been shrouded in mystery. This week his family decided to go public with their quest for answers.

His sister Bridget Allison, 33, of Sebbon Street, Islington, said: “We never found out what happened and why and that has made it much harder to deal with.

“He still had his mobile, so it didn’t seem like a mugging, and there was never any indication it could have been someone he knew. We were just left thinking someone took a disliking to him.

“All the police said was that he wasn’t attacked where he was found, which just leaves it more open.”

All that is known is that Mr Allison, who was 34 at the time, had arranged to meet a friend on August 10 at the Queens pub – now called Millers – in Caledonian Road, King’s Cross, but his friend didn’t make it.

The attack put him in a coma for weeks and he spent more than a year in hospital before being moved into care. He choked to death last August, aged 41, because of swallowing difficulties caused by his injuries. He left behind two children, now aged 13 and 16.

Miss Allison, one of his four sisters, continued: “His children have taken his death really badly. It was a total shock and they blame whoever did this for taking their dad away.

“The last seven years we were just focused on my brother and him getting better. That’s why we never went public before.

“We were also worried about what we might find out. But that’s something we’re now prepared to go through. If we find out what happened, it might help bring about some closure.”

Det Sgt Kerena Hammond, the investigating officer, said: “We are determined to find out what happened. Someone out there knows what happened and I appeal to them to come forward and speak to police in confidence.”

Anyone with information should ring Islington Police on 020 7421 0145 or Crimestoppers on 0800 555 111.