It is safe to say our leader-in-waiting, as probably the only non-scholarship boy in Eton's (to use one of the few Americanisms I can abide) storied history to have housed a Corby trouser press in his room, might be described as vain. It is a flaw which may yet harm us, as was evidenced by the PMQs that preceded this month's Labour leadership challenge.

You may remember Brown, before everything went Hewitt and Hoon, quite obviously discomforting Dave with some sharp comments about his poster-boy appearance. These barbs were written for him by the man who approached me in the corridor afterwards and, with his face inches from mine, looked up and screamed, "HA!" Welcome back, Alastair.

Not for the first time, the ex-pornographer has located our soft spot. It is a weakness of Cameron's that - perhaps because he has spent a lifetime running his hands through, and generally touching up, his hair - photos of him always look airbrushed. Ideally, they might be airbrushed to look not airbrushed, but however much we airbrush, they look even more airbrushed, if you get my drift. Those of us in the know call it the Hairdresser's Dilemma

It is not easily resolved. The need for Cameron to be on the posters is self-evident. If we attempted to woo the electorate with 15ft pictures of Gove they would 1) ask "Who's that?" and 2) go "Ugggh". Nor, the focus groups inform us, would posters of Hague, Hammond or Hunt be any less alarming. So we are stuck with Dave and the way, the larger we make his head, the less lifelike it becomes. He appears almost trustworthy in a normal-sized school photo he has in his loo. (Why do the upper middle classes plaster their loos with pictures of themselves at school? Is it to accompany the crashingly boring reminiscences they roll out during dinner parties?)

But blow him up and he looks, frankly, like a spiv. We have shot him from the right, from the left, even from behind, and it makes no difference. He still looks ever so smooth yet somehow sweaty. Rather like, one imagines, Jacob came across as he stood before Isaac to con his twin brother, Esau, out of his birthright. Not, in short, a sure-fire election-winner - Vote Dave: What's Yours is His.

Yet the alternatives are equally stark. Plastic surgery? If news leaked out it would make Dave seem, if possible, yet vainer. Enforced baldness? It is often forgotten that no political party in the western hemisphere has elected four consecutive bald leaders and survived.