Are you having a laugh? Politicians who can't resist a comedy cameo

Nick Clegg in panto, Boris in the Queen Vic, and now Prezza at Nessa's wedding...

Politics, the saying goes, is show business for ugly people. Unfortunately, some of those ugly people can't resist trying their hand at a bit of light entertainment for real – cluttering up our TV screens with ill-judged cameos in an attempt to boost their political ratings; and it's happening with increasing regularity.

On Friday – New Year's Day – fans of the hit comedy Gavin and Stacey will be treated to a cameo by the former deputy prime minister John Prescott. The pugnacious MP for Hull East will turn up at the wedding of well-proportioned Welsh man-eater Nessa, played by the show's co-creator Ruth Jones, whose character has often hinted at an intimate past with Mr Prescott.

Not to be outshone, Nick Clegg appeared in Jack and the Beanstalk at his local theatre in Sheffield earlier this year in what has become an annual tradition for the Lib Dem leader.

And, in October, the Mayor of London, Boris Johnson, sparked claims of bias when he turned up for a pint in the Queen Vic in the BBC's EastEnders, and had trouble playing himself.

Mr Prescott no doubt believes he is being a sport, and perhaps hopes to emulate the successful cameo by his ex-boss Tony Blair, in a Catherine Tate sketch for Comic Relief in 2007. But it could all go horribly wrong – witness the former Labour leader Neil Kinnock's derided appearance in a 1984 Tracey Ullman video. Mr Prescott's cameo will have added piquancy because of his well-publicised affair with his diary secretary, Tracey Temple.

The cultural commentator Michael Bracewell warns that such appearances rarely pay off. "It's always a disaster," he says. But the PR expert Mark Borkowski says that politicians can earn Brownie points: "In some ways it's genius the way [Prescott] is becoming a parody of himself with shows such as The Class System and Me."

Boris Johnson EastEnders

The mop-topped politician-disguised-as-a-buffoon has often appeared on panel game shows, but not as the real-life Mayor of London. In October he hammed it up in the Queen Vic, with Barbara Windsor, playing a rather wooden version of himself.

Margaret Thatcher Yes, Prime Minister

Yes, Prime Minister was a satire about government so good even the Iron Lady could see the humour in it. She wrote a 10-minute sketch, which she performed with the show's stars – one was Paul Eddington – in 1984.

John Prescott Gavin and Stacey

Prezz-laaaar, as Smithy might call him, will appear in the final episode of Gavin and Stacey, the surprise-hit sit com, on New Year's Day. The former deputy PM will play himself, at the wedding of Nessa, the man-eating character who has often hinted at an intimate past with Mr Prescott.

Tony Blair Catherine Tate

Is he "bovvered"? Certainly not by the critics. The former PM showed a not-so-surprising ability for acting – as well as a deft touch in comic timing – in this appearance as himself with Tate's stroppy teen character, Lauren Cooper, for Comic Relief in 2007.

Charles Kennedy EastEnders Christmas Special

Chat-show Charlie isn't so-called for nothing. A big EastEnders fan, the then Lib Dem leader, seen with Laurie Brett and Adam Woodyatt, appeared in the soap's 2004 Christmas Special as the Ghost of Christmas Future, in a one-off special based on Dickens' A Christmas Carol.

Harold Wilson Morecambe and Wise

There's something about Labour politicians and the stage. The former PM appeared in the 1978 Christmas Special, where he turned the tables on Eric, who would forget the names of guests, by calling him Morry-camby.

Glenda Jackson Morecambe and Wise

OK, Glenda wasn't elected as a Labour MP until 1992, but the Oscar-winner is a rare example of someone able to do both acting and politics. She was Cleopatra in the 1971 Christmas special.

Nick Clegg Panto in Sheffield

Oh yes he did! It's a bit of a tradition for the now Lib Dem leader to show up with the Hallam players in his Sheffield constituency. In March, he was in Jack and the Beanstalk and, in 2004, he appeared in Puss in Boots.

Neil Kinnock Tracey Ullman video

Before helping give birth to The Simpsons, the comedian Tracey Ullman had a string of pop hits in the 1980s. The former Labour leader tuned up in the video to "My Guy" in 1984.

Denis Healey Dame Edna Experience

The bushy-eyebrowed former chancellor showed Neil Kinnock how it's done when, in 1987, he was a silly-billy and sang 'You Either Have or You Haven't Got Style' with Sir Les Patterson.