Boris Johnson threw down the gauntlet to Sir Ian Blair yesterday, declaring that he had the largest personal mandate of any British politician and would push on with his ambition to exert greater control over Scotland Yard.

Mr Johnson told The Times that it was “only right” that the Mayor of London should be able to hold the Metropolitian Police Commissioner, the country’s most senior policeman, to account.

“It’s no secret I think there should be an evolution in favour of democratic accountability between police chiefs and the directly elected mayor,” he said.

His comments came after The Times obtained e-mails in which the Mayor’s senior aides discussed the possibility of suspending Sir Ian from office, pending an inquiry into his friendship with a businessman who has been awarded substantial Scotland Yard contracts.

After the disclosure of the e-mails, Sir Ian risked souring the pair’s relationship further when he expressed concern on Wednesday that his office had become “a matter for high politics”.

Until now, Mr Johnson has highlighted his “productive working relationship” with Sir Ian but has refused to comment further.

However, yesterday he told The Times: “I’ve got a bigger personal mandate than any British politician in history . . . more than a million votes when you count second preferences.

“Londoners in four years’ time are going to hold me to account for crime, for the safety of their streets. They’re going to hold me to account for whether buses feel safer again and whether the Tubes feel safer again and whether we’ve done anything to tackle knife crime.

“In those circumstances, I think it’s only right that there should be a considerable measure of democratic control and accountability for the police chief.”

Sir Ronnie Flanagan, HM Chief Inspector of Constabulary, was appointed yesterday to examine the award of contracts to Impact Plus, a consultancy that was run until last year by Andy Miller, 54, who has known Sir Ian for 30 years and accompanied him on skiing trips. Sir Ian has robustly denied any impropriety. He informed the Met and the Metropolitan Police Authority of his friendship with the businessman in November 2002 and says that he has been open and straightforward about the situation.

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