On at least seven occasions officers have been on the brink of shooting to kill, the Metropolitan Police commissioner told Channel Four News Tuesday night.
Defending the shoot-to-kill policy which resulted in the death of innocent Brazilian Jean Charles de Menezes last Friday, Blair said that in those cases: "We have got as close to calling it as that and we haven't."
Blair said the killing of de Menezes -- who was shot in the head seven times after being mistaken for a suicide bomber -- was a "dreadful mistake" but the police had to protect the public.
"This is professional judgement. There are suicide bombers there and we have a job to do. It is a tragedy that should not divert us from the main issue," he said.
Previously Blair said he could not guarantee no other innocent civilians would be shot as a result of the policy.
De Menezes' death is now the subject of an inquiry by the Independent Police Complaints Commission, which will also examine the use of shoot-to-kill on suspected suicide bombers.