A Spaniard admitted kicking a homeless man in the chest after his friend killed him with one punch outside the National Gallery.
Desmond O’Beirne, 50, was beaten to the ground by Lucas Antunes, 21, in the early hours of June 3 last year.
Luis Abella, 22, then ran over and kicked the unconscious Irishman in the chest.
Mr O’Beirne suffered a serious head injury and clung to life in the Royal London hospital after a screw was fitted in his skull to relieve pressure.
But he caught pneumonia and died last December.
Police had released CCTV of the savage attack which showed Mr O’Beirne running away before Antunes knocked him out with a powerful punch.
Abella then run over and kicked the defenceless Irishman in the chest.
Trevor Green, prosecuting, told an earlier hearing: ‘At 00:25 Mr O’Beirne alone approaches a group of friends. Some 20-15 seconds the victim in the case is then seen to run off. He is then chased by two men.
‘Antunes punches Mr O’Beirne to the side of the head taking him down.
‘He lies in a prone position he does not place his arms out protecting himself. There is then a kick to the torso (by Abella).’
Antunes fled the UK after the attack and was later arrested in America.
He was extradited to the UK and admitted manslaughter at the Old Bailey last week.
Abella, of Marshall Court, Studley Road, Stockwell, admitted attempted assault causing actual bodily harm at the Old Bailey today (fri).
Both men will be sentenced on February 8.