Metropolitan Police Commissioner Sir Ian Blair has admitted somebody else could be shot as a result of a national "shoot-to-kill in order to protect" policy towards suspected suicide bombers.
He was speaking after formally apologising to the family of the innocent 27-year-old Brazilian electrician shot five times through the head by officers at Stockwell tube station on Friday morning.
On Friday, Sir Ian told a press conference that the shooting was "directly linked" to the ongoing and expanding anti-terrorist operation. But in a statement issued on Saturday afternoon the Metropolitan Police admitted they had got the wrong man and that the victim, Jean Charles de Menezes, had no terrorist connection.
What Sir Ian described yesterday as "a tragedy" has added hugely to the pressure already on police to find the four suspects believed to be responsible for last Thursday's unsuccessful attempt to bomb three tube trains and a bus.
Police are investigating a possible link between Thursday's failed bombing attempts and those responsible for the July 7th attacks which killed 56 people.
They carried out two controlled explosions yesterday on a suspicious package found in Little Wormwood Scrubs in northwest London which may have been linked to the bombs recovered on Thursday. And a third man was arrested in the Tulse Hill area in which Mr de Menezes lived last night, while two others arrested on Friday were still being questioned by police.
It appears Mr de Menezes may have lived in a multi-occupancy house in Scotia Road, Tulse Hill, in south London, which was placed under surveillance following Thursday's failed attack on the capital's transport system.
Police were reportedly led there by their own intelligence and by documents recovered from abandoned rucksacks.
Confirming that the Independent Police Complaints Commission would conduct an inquiry into the fatal shooting of Mr Menezes, a Scotland Yard spokesman said they were now satisfied that he was not connected with last Thursday's events. "For somebody to die in such circumstances is a tragedy and one that the Metropolitan Police service regrets." Former minister Robin Cook joined some Muslim leaders in demanding a review of the acknowledged shoot-to-kill policy, while relatives and friends of the dead man staged a vigil at the scene of his death and a protest in Westminster.
One relative, Alex Pereira, re-enacted his cousin's final journey on foot and by bus to illustrate his belief that the police had "plenty of time to stop him".
Brazilian foreign minister Celso Amorim met foreign office officials in London yesterday and spoke to foreign secretary Jack Straw by telephone in search of an explanation for the shooting.
While declaring Brazil "in solidarity with Britain in the fight against terror", Mr Amorim said his government was "shocked and perplexed that a peaceful and innocent person should have been killed". As they prepared to fly his body home, meanwhile, family members said Mr de Menezes had worked legally in London for more than three years, spoke good English, and had no reason to fear or flee the police.
Sir Ian said the dead man "was challenged and refused to obey police instructions" and witnesses saw him jump over the barriers at Stockwell station as some 20 officers gave chase.
While accepting full police responsibility and expressing his own "deep regrets", however, Sir Ian confirmed there would be no change in the "shoot-to-kill to protect" procedures which had been introduced based on the experience of other countries, including Sri Lanka.
The policy had been "reviewed and reviewed" he said, and was a national one and not just for London.