A judge yesterday blasted Britain's violent yob culture after hearing how a feral gang beat a disabled man to death for a £5 bet.

William Hughes, 23, and two mates aged just 16 and 17, killed gentle giant Brent Martin, 23, for sport as he begged them for mercy.

The boy of 17 was convicted of murder yesterday just a week after three yobs were locked up for killing dad Garry Newlove in a senseless attack which shocked Britain.

Judge John Milford QC called for a police probe into whether killers were getting younger.

Hughes and the boy of 16 had already admitted murdering Brent, who had psychiatric and learning difficulties, after betting they could knock him out.

Jurors wept as they heard that the gang followed him for a mile through Town End Farm, Sunderland, punching and kicking him unconscious.

Tony Hedworth QC told Newcastle crown court: "They behaved like a pack of animals."

Brent, who had spent £3,000 savings buying booze so they would be his pals, told them he loved them as they beat him in August. They asked a passer-by to take a photo of them "happy and proud" as he lay injured from 18 blows to the head.

Brent died in his mum's arms two days later. He had spent nine years in hospital and had just been released weeks before.

Hughes and the boys, who can't be named, face life in jail.