Metropolitan Police Commissioner Sir Ian Blair admitted Saturday he did not know his officers had killed an innocent man until 24 hours after the shooting of Jean Charles de Menezes in the Stockwell Tube last month, the London Telegraph reported.
A Downing Street spokesman said Blair had "full confidence" in the police commissioner and his handling of the case.
Blair's support was echoed by deputy Prime Minister John Prescott, who is in charge while the prime minister is on vacation.
The police commissioner faced further criticism Sunday after published reports that that Scotland Yard had offered the dead man's family a $27,000 payment.
Prescott said he had not seen the letter containing the alleged offer, but said it would be "terrible" if the reports were true.