The Big Smoke

Just as the previous Mayor benefited from a ‘Ken will be Ken’ attitude among the electorate for the bulk of his eight year reign allowing him to get away with all manner of petty infractions, Boris Johnson has so far been able to ride the waves of incompetence emanating from City Hall with a self-deprecating shrug of his shaggy shoulders. 'Boris will be Boris'.

But it wasn't supposed to be this way: politically, this was meant to show that Tories do care about local government and are ready for high office; personally, Boris was going to shake off the suspicion of silliness that clings to him and enhance his own credibility as a first-class politician.

So while Boris remains popular despite the series of high-profile resignations from the GLA, there is little doubt the departures of McGrath, Lewis, Parker and Clement (have I missed any?) will take their toll. If the next three years are anything like the first – and there’s no reason to think they won’t - Boris will no longer be considered a credible candidate for serious political office. Put it this way, if Boris was running the Department of Health the way he was running London, he’d have been out on his ear by now. Prime Ministers – whatever their own personal failures – can not stand by and allow underachieving gaffe-prone ministers to remain in power.

In that sense, the threshold for ministerial competence is held to be much higher than than of the Mayor, largely because the Mayor is democratically elected and accountable to the people, not to internal politicking. But what that means is that if Boris makes himself available to David Cameron in 2012 – as he has hinted he might – the then Prime Minister will find it very easy to ignore the raised hand of his most popular – and personally threatening – fellow Tory, and keep the loose cannon out the Cabinet. And Boris's dream of becoming Prime Minister himself is, at present, completely implausible. Cameron, who has already distanced himself from Boris's performance as Mayor, will be delighted that Johnson is no longer a threat to his authority.

So while Boris would have a very good chance at securing a second term if he runs again for Mayor (as he now insists he will), he is all but unappointable as a Cabinet Minister. The same was true of Ken Livingstone of course, but his situation was far more complicated (he ran first as an Independent and was never likely to win the favour of New Labout), and Livingstone, for all his faults, at least managed to turn the office of Mayor into one of the most important and effective political jobs in the land; Boris, by contrast, has managed to reduce it to the status of glorified council leader, and seriously damaged his own political ambitions into the bargain.

PS Dave Hill has come to a similar conclusion.