The Guardian reckons that Ian Blair is a bit of a lying scumbag:
The commissioner of the Metropolitan police has repeatedly said that he was unaware that the victim was not a suicide bomber until 24 hours after the Brazilian was shot on July 22 2005, a day after several attempted attacks on the London transport system by terrorists. But several witnesses have told the Independent Police Complaints Commission inquiry that senior officers feared within hours of the shooting that the wrong man had been killed after being mistaken for a terrorist.
Oops. So it looks again like Blair is either a) an incompetent tool who had no clue what was going on, or b) a bare faced liar:
one senior police source told the IPCC that by that afternoon, top officers were working on the assumption that "we got the wrong person ... we better plan around this being a mistake." Another source inside the Met's headquarters that day said every senior officer he spoke to believed that Mr de Menezes was not a terrorist: "I don't know how Ian could not have known."
Blair himself has always insisted he knew nothing of the sort. "The key component was that at that time, and for the next 24 hours, I and everybody who advised me believed the person shot was a suicide bomber."
And if you read it in the News of the World you know that it's TRUE.