A former officer in the Irish police caused fatal brain injuries to a drunk man in an attack born out of "frustration and irritation", a court heard.
Oliver Hurley, 64, is said to have shoved Manolito Chando, 56, so hard he lifted him off his feet during a confrontation at a Salvation Army hostel close to London's Westminster Abbey.
The court heard the alleged victim was drunk and unsteady on his feet when the former garda violently pushed him out of a lift at around 8pm on March 24 last year.
That evening Mr Chando, who had a history of alcohol abuse, had been behaving in an "irritating way" towards other residents in the home for "adult males with varying support needs", jurors were told.
"The prosecution case is that the assault that followed, when the defendant shoved Mr Chando out of the lift, was born as much of frustration, irritation, on the defendant's part as anything else," said prosecutor James Brown.
"He described Mr Chando, in a police van later that evening, as 'a pest'."
The alleged victim was taken to hospital with a small bleed on the brain, having regained consciousness eight minutes after the alleged attack.
But he was put into an induced coma after his condition deteriorated and doctors took the decision to give no further treatment on April 9.
A coroner found Mr Chando had died from a "traumatic brain injury" and Hurley, of Wandsworth Bridge Road, in Fulham, southwest London, is standing trial at the Old Bailey, where he denies manslaughter.
The prosecutor told jurors: "This trial concerns the death of a man called Manolito Chando. The defendant is charged with his manslaughter, that is to say his unlawful killing.
"Mr Chando died on April 9 last year. The Crown's case is that his death was as a result of injuries he sustained when he was violently pushed to the ground by the defendant a number of days earlier on March 24 the same year.
"The issue for you to determine is whether the defendant was acting in lawful self defence when he pushed Mr Chando to the ground.
"There may also be an issue raised by Mr Hurley as to whether or not the injury inflicted on Mr Chando was in fact the cause of his death."
Jurors were shown CCTV footage of the alleged attack in which Mr Chando appears to be unsteady on his feet as he steps back out of the lift into the foyer of the hostel.
"The defendant violently pushed him backwards with sufficient force to lift him off his feet," Mr Brown said.
The trial continues.