Politics, the old joke goes, is showbusiness for ugly people. But that joke might be on the way out: if you have a great face for local radio, that might no longer be enough if you aspire to hold public office.

Our mothers always told us to sit up straight and smile when meeting others, though even mums would baulk in the face of 24 hour rolling news, where you’re instantly judged on your public profile, and your personality is suddenly political. When a man can be pilloried for the indecorous eating of a sandwich, you may feel nostalgia for, say, the time when Churchill was incapacitated by a stroke, and it took his own ministers weeks to find out.

Image is a slippery thing: Boris Johnson is photographed stuck on a zip wire, and readers shake their heads with an amused chuckle over their cornflakes the next morning. Ed Miliband struggles with a sandwich, and a Labour MP in a marginal seat groans and turns to the situations vacant.

‘Authenticity’ is the watchword of our new book, Insider Secrets of Public Speaking (and here’s the first secret – it’s available on Amazon but keep it under your hat, because it hasn’t been officially launched yet). You can’t change what you are, and you shouldn’t fake it, so you just have to embrace it.

The first time Mrs Thatcher was called ‘the Iron Lady’ it was meant as an insult. The tag stayed with her all the way to her obituary headlines and beyond, and probably did more for her image than any number of voice exercises.

A good personal brand is infectious: ‘Boris bikes’ were really Ken Livingstone’s idea, but the sight of the present Mayor wobbling along in a helmet and trouser clips sticks in the mind. Here is the trick, with Boris: he doesn’t take himself seriously, but if you get him on the problems Londoners face, he becomes sincere, practical and thoughtful. ‘Your problem is important,’ he seems to be saying, ‘more important than my dignity.’ If it’s a trick, it’s a very good one.

Bullies only want a reaction, and so do the press, though the reaction they want is to sell papers. Ed Miliband’s admission that he may indeed look a bit like Wallace from the Wallace and Gromit animation is an attempt to get beyond not only his public image problem (which would be bad enough) but his public image of someone who has a public image problem (which is worse). If politics is showbusiness for ugly people, at least the (perfectly pleasant-looking) Labour leader should be pleased to resemble the recipient of so many Oscars.

Conclusion: it’s ok to know you’ve got a problem and it’s ok to fix it. But perhaps you’re not the best person to judge whether it really has been fixed or not: that’s a call for others to make. Don’t let on that you’ve hired an image consultant until they prove they’ve been worth their fee. And if you can carefully cultivate the image of someone who doesn’t care about their image, you’ve really hit gold.

PS Programmes deliver presentation skills, TV and radio media training and crisis media management, tailored to the needs of our clients. This article appears on http://www.presentationskillsprogrammes.co.uk and http://www.nadinedereza.com/