Sometimes you just can't keep a good television hero down -- even when he's dead. Take Jim Taggart, the gritty, steely-eyed Glasgow homicide detective, played for 11 years by the gritty, steely eyed Glasgow actor Mark McManus. In a sane world, McManus's death in 1994 should have spelled the end of the series, or at least prompted a title change to reflect the fact that its leading star had departed to that great TV studio in the sky.
But no. Taggart carried on, in name if nothing else, propped up by a revolving cast of formerly supporting characters for a further 17 years. It was finally interred earlier this year when the ITV network shouted: "No more!"
The last time we looked, Charlie Sheen was still alive -- although going by his gaunt, stringy appearance at this week's Emmy awards, and later on Comedy Central's roast in his honour, we should qualify that statement with "just about".
Sheen's increasingly manic behaviour and rant against Chuck Lorre, creator of Two and a Half Men, which resulted in him being fired from the sitcom, should ensure that at least his career as a TV star is dead. Although in Hollywood, home of celebrity rehab and resurrection, you just never know how these things are going to pan out. Put it this way, if Mel Gibson can still walk around in daylight without being lynched at every street corner, there's hope for anyone.
One thing is for sure, though: Sheen's character in Two and a Half Men, hedonistic jingle writer Charlie Harper, is definitely dead as a doornail. The first episode of the new series opened with Charlie Harper's funeral. Against all expectations, the producers of Two and a Half Men decided to gamely carry on and cast the terminally vapid Ashton Kutcher as a new character, divorced internet billionaire Walden Schmidt, who, like his predecessor, has something of a way with the women.
But the reactions to the change in the US has been lukewarm at best, and the expectation is that it won't be long before Two and a Half Men joins Charlie Harper in his grave. Sheen might be as mad as a boatful of yodelling monkeys, but there's no denying he was the glue that held this rickety sitcom together.
History shows that when a popular series loses its leading character, or the actor playing that character, its fortunes nosedive. When Michael Douglas left The Streets of San Francisco, Richard Hatch proved a weak foil for Karl Malden.
When Barbara Bel Geddes quit Dallas, to be replaced by Donna Reed, there were howls of protest. Geddes was lured back.
The Waltons didn't survive long after the departure of Richard Thomas, aka John-Boy.
The X Files died a slow death once David Duchovny quit. Midsomer Murders staggers on, minus John Nettles -- although some would argue it has never exhibited any signs of life.
There is the odd positive precedent. NYPD Blue survived several cast replacements after David Caruso left.
But if Two and a Half Men lasts more than one more series, it will be a miracle akin to the Second Coming of Mickey Rourke.