This comeback is deceased

What is it about old stars that keeps them hanging on and on and on?

It is a hazardous business, making a comeback. It's a risk many stars can't resist. The latest are the Monty Python team who are threatening to make a 30th anniversary reunion tour. Given their self-deprecating wit and undoubted talent they may carry it off, without being laughed off stage as a bunch of sad, superannuated comics.

They should avoid the toe-curling embarrassment of the Monkees last year in their comeback concert tour. "The musical equivalent of watching a road accident", as one critic put it.

Yet despite the pitfalls, despite the risk of utter humiliation, there appears to be an irresistible force that plucks showbusiness personalities out of retirement and propels them back into the fickle limelight. This year it is the turn of, among others, Leo Sayer, the fuzzy-haired crooner who enjoyed a brief period of stardom in the 1970s.

Singers seem particularly prone to this kamikaze impulse to gamble what reputation they once had, however small, in exchange for an opportunity to strut their stuff once again. Paul Young, for instance, who made an insignificant impact on the music scene in the 1980s is trying again, without overwhelming success, to rekindle interest in himself.

But other types of has-been performers, including actors and comedians, are equally weak-willed when it comes to resisting the siren call to return to the public eye. As for sportsmen, particularly boxers, so routinely do they pop up again that retirement has become an entirely relative concept.

Why, then, do apparently sane men and women persist in impaling themselves voluntarily on the sharp knives of critics, in offering themselves up for ridicule like sacrificial lambs?

Money, clearly, is an important incentive; in the music world, for instance, there is the time-honoured tradition of the "tax-bill reunion tour". When the Sex Pistols got back together in 1996 for what they dubbed The Filthy Lucre Tour, they earned themselves an estimated pounds 1 million apiece. Pete Townshend said of The Who's reunion tour in 1989: "I did it purely for the money."

Often the motivation can be far more complex. Once fame and adulation have been tasted, however briefly, they create a craving that becomes difficult to shake off. So, you work hard, become successful, then retire in a blaze of glory, and a few years later you suddenly yearn once again for the bright lights and the stretch limo, and convince yourself that the fans wish you had never gone away. Or, you wake up one day with a pot belly and a midlife crisis, and decide to stage a comeback to prove that you are as hugely talented as ever. Alternatively, your ego is so immense that it cannot be contained.

Matt Snow, editor of Mojo, the music magazine, said: "Some people just can't keep out of the limelight. Being the centre of attention is very, very addictive, and when you lose it, it can be quite a wrench."

Mark Borkowski, who runs a public relations firm, said he could understand why the Monty Python team wanted to re-form. "They have all pursued successful careers apart," he said. "Now they have got together and have been seduced by the idea of seeing whether they can still make people laugh in the old way."

Comebacks, anyway, need not be disastrous. Eric Sykes, the veteran comedian, was a great hit when he returned to the West End last year at the age of 73. John Travolta, never taken seriously in the 1970s, was a critical success when he returned to acting in Pulp Fiction in 1995. Julie Christie, the 1960s film star, has been nominated for an Oscar for her role in Afterglow. Barbara Windsor, the Carry-On actress, has reinvented herself as a matriarch in EastEnders. And Gary Glitter, the eternal comeback kid, carries it off because his whole stage persona is a parody.

Sometimes, a sense of nostalgia helps to prevent a return to the public eye from being a flop. In other cases, a new generation may re-discover the appeal of oldsters such as the comedian Bob Monkhouse, 69, who has acquired a cult following since appearing on the BBC's Have I Got News For You two years ago.

For comeback boxers such as Joe Bugner, George Forman and Frank Bruno, going back into the ring can be highly lucrative. When Mike Tyson fought for the first time after being released from prison, he earned pounds 30 million in one night. But the purse is not the only lure, according to Ken Jones, The Independent's boxing correspondent.

"Boxers who quit can find it very difficult to get it out of their systems," he said. "They get a strange thrill out of going into the ring, and there is a big anti-climax when they give it up."

For rock stars and sportsmen, whose shelf life is particularly short, the desire to recapture some of the old magic is easy to comprehend. But those who do succumb to temptation should ensure that they have a thick skin. For that way, in the majority of cases, ignominy lies.