Sir Ian Blair is appointed by Home Secretary Jacqui Smith, so Johnson cannot actually fire him, The Times of London reported. But Johnson is also expected to take on the job of chairman of the Metropolitan Police Commission -- which would allow him to hold a vote of no confidence and would put considerable pressure on Smith.

Johnson was pugnacious in his speech claiming the mayor's job, the newspaper said. He told officials he expects them to recognize the Conservative victory against former Mayor Ken Livingstone.

"If there are any dogs in the manger, then I will have those dogs humanely euthanized," he said.

He said his staff is trying to make sure no evidence of corruption in the Livingstone regime is being shredded.