Boris Johnson, the Mayor of London, has defended his decision to force the resignation of Sir Ian Blair as Metropolitan Police Commissioner and denied that it was politically motivated.

Mr Johnson said today that it was Sir Ian’s decision to step down and rejected criticism from Jacqui Smith, the Home Secretary, that he had brought party politics into policing.

“There is no party political element to this,” said the mayor.

“I simply thought after long reflection and widespread consultation that it was a good opportunity for someone else to offer new leadership, stability and increased operational effectiveness, for the Metropolitan Police and that was not an opportunity that I could let go by...

“The decision that we came to - and I stress that it was his decision following a conversation with me - the decision that he came to very much reflected the flavour of conversation that I had with a great number of people with responsibility for London policing and it was my view that I could not shirk the advice I was being given.”

Mr Johnson and his team are known to have been frustrated that the internal politics at Scotland Yard has detracted from the business of policing London.

They moved to oust Sir Ian on Wednesday within hours of taking control of the Metropolitan Police Authority.

The commissioner agreed to step down and informed Ms Smith yesterday morning. Sources confirmed that Sir Ian also spoke to the Prime Minister by telephone yesterday lunchtime.

Ms Smith told the BBC that Mr Johnson had chosen to ignore the correct procedures for seeking a commissioner’s resignation.

“What is important when you are both choosing and when you’re supporting somebody that you’re asking to do a job like that is that you keep party politics out of it,” she said.

“You need to work alongside people and, frankly, you should put some time and effort into that.”

Sir Ian is to remain in post until December 1 to allow the process of selecting his successor to get underway. He was not at Scotland Yard this morning, however, and the Friday management board meeting was chaired by Sir Paul Stephenson, the Deputy Commissioner.

Sir Paul will take over as Acting Commissioner when Sir Ian leaves and is the bookmakers’ favourite to succeed to the post permanently.

Ken Jones, president of the Asssociation of Chief Police Officers, gave a warning against the politicisation of policing.

“We do need to avoid the politicisation, even by implication, that we see in some American forces where law and order and politics are bound together in a toxic way. We can’t ever get to a position in this country where that happens.”

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