The one thing that TV executives enjoy more than finding a new hit sitcom is declaring the sitcom to be dead, depicting it as some kind of prehistoric beast that once roamed the TV schedules devouring all in its path, but whose era has long since passed. But that never stops them hunting for a new one. It is the holy grail of television.

If you want a TV show that will still be syndicated on cable channels when your great-grandchildren are born, find a successful sitcom.

From I Love Lucy and M*A*S*H to Seinfeld and Blackadder there is no richer seam of TV gold than the situation comedy. Which explains why the BBC is reworking a Rising Damp for the 21st century, hoping to tap the success of the original. Simon Nye, who created Men Behaving Badly, is turning Leonard Rossiter's Mr Rigsby into a landlady and transplanting her to a North London guesthouse inhabited by migrant workers from Poland and Iran, alongside young professionals frozen out of the property market by dizzy house prices and the credit crunch.

Will it be a success? Who can predict? But what is certain is this: if it is not, it would still be as senseless to cite its failure as proof that the sitcom is dead as it would to open a bottle of claret that's corked and to declare that wine is over.

In a panel discussion at the just-ended Edinburgh International Television Festival, the corpse of the sitcom was once again prodded for signs of life. Michael Grade, the ITV boss, aches for a sitcom to win prime-time audiences. In America, TV studio executives will sell their grandmothers for a sitcom that can deliver the ratings of Cheers or Friends or Seinfeld or Frasier.

It is fashionable to suggest that the sitcom has evolved. That the half-hour comedy filmed in front of a studio audience has metamorphosed into The Royle Family and The Office. That Scrubs and The Thick of It have led the sitcom in a new direction. But The Thick of It, with its shaky camerawork, and with swearing that would make Gordon Ramsay wince, is not so very different from Yes Minister. Ricky Gervais's David Brent in The Office looks as modern a confection as mango smoothies, but he shares a comic DNA with Basil Fawlty, Tony Hancock, Captain Mainwaring and Harold Steptoe - men flawed by their belief that life has dealt them a hand far beneath their talents, imprisoning them in a world that they know they will never escape.

My Family, among the most successful British sitcoms of recent years, was built on the trusty American formula of sprinkling the script with one-liners. Which is why, when Mr Rigsby's re-incarnation comes to fill our screens, pundits should not bother trying to judge whether the show confirms or debunks the case for the sitcom being dead; or whether it reflects contemporary Britain back at today's television viewers.

As with Mark Twain's premature obituary, the reports of the sitcom's death are greatly exagger-ated. Sitcoms are not alive or dead. They are funny or not funny. The odds of success are as slim as those of David beating Goliath: but when they do succeed, their triumphs are just as legendary.