A BOY of 14 was chased and stabbed to death by a teenage gang because he gave them a dirty look, a court heard yesterday.

Martin Dinnegan is said to have repeatedly screamed please help me as he tried to outrun at least four youths riding bikes and mopeds.

He was cornered then punched, kicked and stabbed in the back four times, the jury heard.

He bled to death just an hour after the row began.

Prosecutor Aftab Jafferjee QC blamed the killing on the growing scourge of urban posturing.

He said it involves aimless meandering by groups prepared to exploit any pretext to engage in violence.

Martin and his pals were on a bus in North London when dirty looks were exchanged with another group on bikes, the Old Bailey heard.

Blows

The gangs later clashed on an estate in Holloway and a boy of 16 was stabbed in the shoulder.

Martin fled but the other gang armed with screwdrivers and knives followed and rained blows on him, the court heard.

A witness heard an attacker say: You want to play with knives, I will show you what knives are, it was said.

One blade passed right through Martins body. He also had a cut between his thumb and forefinger typical of a defence injury.

Rene John-Baptiste, 21, of Plaistow, Sean Clark, 19, of Holloway, a 17-year-old and a 16-year-old all deny murder.

The trial continues.