One morning in May 2008 I walked in to the office to find a scene of quiet desolation. Colleagues barely looked up, long faces fixed on their computer screens. Nary a smile was to be seen nor a gay word to be heard that day, for the long-feared catastrophe had duly come to pass. Yes, Boris Johnson had been elected Mayor of London.

It seems that my co-workers took the same view as the Guardian which, in an unintentionally hilarious edition, warned of the terrible dangers to the capital if the Tory MP and Telegraph columnist were to eject Ken Livingstone from "the glass testicle", as City Hall is known.

"Boris Johnson in the role of mayor would feel like being trapped on the set of The Wizard of Oz minus the soundtrack and the Technicolor," said Bonnie Greer, in yet another of her wise and pithy observations that so enrich the commentary of our nation, while Arabella Weir declared: "I will go on hunger strike and throw myself in front of the next horse at Ascot if he wins."

Yet Big Ben still stands, the ravens have not flown the Tower of London, the rubbish is collected with the same regularity from outside my home in Camden, and preparations appear to be on track for what we are exhorted to regard as a great symbol of civic pride, though I prefer to think of it as a useless drain on the public purse: the 2012 Olympics. Oh, and fortunately Ms Weir still lives, too.

Having Boris in charge has not been the disaster many predicted, but it is already being painted as such now that Labour has selected its candidate for the next mayoral election. Perhaps anticipating that he would defeat Oona King for the nomination, Ken Livingstone has already been training his fire on his successor since launching his campaign in June.

Now many may expect the New Statesman to support Ken's campaign; and perhaps the magazine will when our one-time guest editor comes to battle it out with Boris. But if so, it should be for the right reasons -- which were notable by their absence in the whipped-up furore about the possibility of Boris winning last time.

The main arguments then were: he was an Old Etonian; he had a plummy voice; over the course of thousands of columns he'd made a few comments that could be taken out of context and presented as serious statements (instead of the jokes they actually were) in order to "prove" that he was a racist; and, er, he was a Tory.

The first two are true, but I fail to see how they disqualify him, unless one takes the view that discriminating against someone on the basis of their class background is acceptable. (Surely not -- imagine the outrage if anyone suggested Ken's education at Tulse Hill Comprehensive was a reason not to vote for him.) I don't believe for a minute that Boris, who is of Turkish extraction and whose mother-in-law is Indian, is racist. (He may be guilty of stereotyping for comic effect, but he is an equal opportunities disher-out of cheery abuse.) And yes, he is a Tory.

If this is really all it came down to -- not: what kind of a Tory is he? What will he do for London? How successful has he been at running an organisation before? -- then it was all mere tribalism. Pathetic, narrow-minded, self-interested, self-absorbed tribalism. Alas, I fear it was. None of the people I spoke to who were sunk in gloom the day after Boris's victory could point to any particular dreadful consequence that they feared. It was just that he was a Tory, and therefore it was a terribly BAD THING that he had been elected.

In fact, a mayoral candidate's party affiliation isn't necessarily the point at all, as Ken Livingstone knows well. He won the first mayoral election, remember, as an independent after New Labour stitched up the internal selection process to ensure he wasn't their candidate. We have more than enough party politics in the capital, what with the London Assembly and our councils, most members of which do indeed owe their positions to their advertised political attachments. But a directly elected mayor is bigger than party.

What is important is the individual and the sentiment they inspire in the cities they run. Do I feel safe, and that my neighbourhood is well policed? Are the streets clean? Are the local services of a good standard (such as the excellent community libraries near me in Chalk Farm and Belsize Park, both of which Labour tried to close down last time it was in power in Camden)? Does London feel like it's thriving, while taking care to ensure that the old, the needy, the sick and the poor are not only provided for, but cherished?

No matter that some of the above are not in the mayor's purview. A great mayor sets the tone for a city, for good or ill. You may prefer an Ed Koch to a Rudy Giuliani, but either way you know what kind of New York they represented. (By contrast, does anyone even remember the name of David Dinkins? And how many of us could correctly identify which parties the three former mayors belonged to?)

Having said that it is about the individual, there may be some who do object to Boris's accent, his hair, his humour, etc. Fair enough -- though it would be hard to make the case for why such attributes should count seriously in an election. What matters is how he, or anyone else, can do the job. There will undoubtedly be millions of Londoners who think that Ken would make a better mayor than Boris, possibly sufficient for Livingstone to return to the office that his lifetime in politics led up to.

So do, indeed, vote for Ken when the time comes, should you wish. But do so because Ken is Ken, not because he wears a Labour rosette, just as many voted for Boris because of who he was, not because he was a Tory. If that were all that counted, then the proverbial donkey could end up winning the mayoral election.

There is precedent, of a sort, for this -- the emperor Caligula infamously wanted to make his favourite horse, Incitatus, one of Rome's two consuls. But I hardly think his is an example we would want to follow today. This is a case where the political should not be tribal, of either the equine or the bovine variety, but personal.