Aaron Cole, 19, James Pearce, 19, and David Huggins, 18, took part in an attack on the 17-year-old "as savage as it was senseless", Judge Geoffrey Grigson told the Old Bailey.

The victim's father said after the trial he wants the men to be locked up for good.

"Whatever happens, it will not bring my son back. They should be put away and never let out," he said.

He may launch a civil prosecution of two defendants who were acquitted.

Jamie: 20 different injuries

Steven Plank, 18, and a 16-year-old who cannot be named for legal reasons walked free at the end of the trial last month.

All five teenagers, from Rotherhithe, had denied murder.

A gang of at least six youths set upon Jamie with snooker cues and bats on a street in Rotherhithe's Osprey estate, south London, in August 1997.

He died from 20 separate injuries including cracked ribs and skull fractures, after being hit 40 times.

Police officers said they faced an immediate "wall of terrified silence" when they tried to speak to witnesses.

Many spoke only after police launched a hugely expensive witness protection scheme, moving some witnesses and even their family and friends from the area.

MP's help

When Jamie's family leafleted for information about the killers, they generated so much hostility on the estate they had to be given police protection.

The case was eventually taken up by local Liberal Democrat MP Simon Hughes, who assured witnesses they would be protected from possible reprisals and their anonymity guaranteed if they gave evidence.

He also arranged for the deportation of an illegal immigrant to be overruled, because his evidence was so valuable to the inquiry.