A British inquest ruled on Tuesday that an Angolan man was unlawfully killed during his deportation by three guards from the firm behind the London Olympics security fiasco.

Jimmy Mubenga, 46, was restrained with "unreasonable force" by the guards from G4S in October 2010 on a British Airways flight to Angola, a jury ruled.

The father-of-five was held down after allegedly attacking the guards. The plane was stopped on the runway at London's Heathrow Airport after he was found to be not breathing.

Mubenga was taken to hospital but died of cardio-respiratory collapse.

Britain's Crown Prosecution Service said it would now reconsider a decision not to bring criminal charges against the guards, Terence Hughes, Stuart Tribelnig and Colin Kaler.

In English law, inquests are held to examine sudden or unexplained deaths. They set out to determine the place and time of death as well as how the deceased came by their death, but do not apportion blame.

G4S said Mubenga's death was a "tragic event" but insisted that it had "acted appropriately and in full compliance with the terms of our contract" with British border authorities.

G4S faced an inquiry by British lawmakers after it announced just days before last summer's London Olympics that it could not completely fulfil its ??284-million contract to provide 10,400 security staff for venues.

Britain was forced to draft in thousands of extra troops to make up the shortfall.