These four teenagers have been jailed over an hour of "fun" in which they attacked eight people, killing a barman who survived the Soho nailbomb of 1999.

On Monday Reece Sargeant, 22, Darren Case, 18, David Blenman, 17, and Chelsea O'Mahoney, 15, were sentenced to a total of 44 years for their night of violence on London's South Bank.

Yet police said they were "deeply disappointed" that the jury convicted them only of manslaughter, and not murder.

Head kicked like football

The Old Bailey heard earlier how O'Mahoney kicked bar manager David Morley's head "like a football". The 37-year-old suffered 44 injuries, described by a pathologist as the kind seen in people who had fallen from a great height.

When the Admiral Duncan pub in Soho was bombed seven years ago, Mr Morley helped others despite his own wounds. But on 30 October 2004, sixteen hours after the attack by Sargeant's gang, he bled to death from a ruptured spleen and five broken ribs. Even an emergency operation could not save him.

'All-nighters'

The Chelsea bar manager was one of eight people punched, kicked and stamped upon by the four youths within less than an hour.

A 15-year-old friend told police she heard the four planning how they would beat up "tramps, druggies or just people on the street" in the early hours. Their cue to attack would be if one member asked a victim the time. The gang called their exploits "all-nighters".

CCTV footage shows how O'Mahoney filmed part of the attack on the last victim, Wayne Miller, on a mobile phone. The four set upon Miller where he was sleeping in a doorway in Leake Street before they ran off "whooping" in delight. Fingerprints of Case and Blenman were found on the metal doorframe.

The first attack, on David Dobson in Lower Marsh at around 2.30am, was also partly captured on CCTV.

Mr Morley and his friend Alistair Whiteside were sitting on a bench near Hungerford Bridge when the gang struck, knocking them both to the ground.

Five minutes later witnesses saw another unprovoked attack on three men chatting on a bench nearby. They were Frank Pitassio, Vincent Biasizzo and Daniel Olivera.

Then the gang hit Nigel Elliot over the head with a bear bottle where he was sitting alone in Jubilee Gardens at the London Eye. The bottle, found at the scene, was also covered in Mr Pitassio's blood.

Boasting to girlfriend

Both Mr Pitassio and Mr Whitehead's mobile phones were stolen. An hour after the rampage Sargeant called his girlfriend from Mr Pitassio's phone, boasting to her that he stole it.

Officers seized O'Mahoney's diary when they searched the girl's home in South Norwood. It mentioned how "them lot bang up some old homeless man" in a separate assault earlier that month, later verified by police.

Gang leader Sargeant, Case and Blenman, all from Hotspur Street in Kennington, south London, were each sentenced to 12 years for manslaughter and six years for conspiracy. O'Mahoney was jailed for eight years for manslaughter and five years for conspiracy.

The court ordered name bans on the two under-18s to be lifted.

'Extremely disturbing'

The Met's Assistant Commissioner Tarique Ghaffur was "deeply disappointed" that the murder trial resulted only in manslaughter convictions. Homicide detectives would work with prosecutors to see if any lessons could be learnt, he said.

The youths' "complete disregard" for Mr Morley's life and the way in which they filmed the attack as a "trophy" was "extremely disturbing", Mr Ghaffur added.

Mr Morley "came to symbolise what is good in human nature", said Detective Chief Inspector Nick Scola, who led the inquiry. "For him to lose his life in such a cowardly and pointless attack was a tragedy in every sense of the word."