He who lives by the sword...

Sir Ian Blair's resignation as Metropolitan Police Commissioner had an air of inevitability about it.

I have long thought that Ian Blair was the wrong person to lead the Met Police. The aftermath of the shooting of Jean Charles de Menezes indicated that either he was prepared to make statements to the press that he knew not to be true or his senior officers failed to keep him informed of the true situation. Neither inspired confidence in his leadership.

What is slightly surprising about his departure is that what did for him in the end was not the shooting of de Menezes, the various racial discrimination cases or the allegations that contracts were awarded inappropriately: it was politics.

And this is a highly appropriate reason for him to go, as Blair himself was one of the most politicised police figures I can remember. His interventions on the debates on detention without charge for 90 or 42 days were highly inappropriate for a serving senior policeman. Blair allowed himself to become very closely identified with the New Labour establishment, which made his position rather fragile when Tory Boris Johnson was elected as Mayor of London.

That said, the manner of his departure is highly questionable. As Lib Dem mayoral candidate Brian Paddick said when interviewed about Blair's resignation on Radio Five Live this afternoon, this looks like an arbitrary decision by Johnson. Paddick pointed out that the correct procedure if Johnson had concerns about Blair would have been to have organised a vote of no confidence in him on the Metropolitan Police Authority. It is utterly wrong that Johnson has now given the impression that the police should be subject to political diktats.

The job of Met Police Commissioner is a tough one. I just hope that the next Commissioner realises that his or her job is to concentrate on policing rather than politics. And I hope that the politicians allow that person to do their job without interfering at every step.