In the world of stand-up comedy the issue of plagiarism is a light sleeper, it doesn't require much to wake it. My review of Tim Vine's show last week mentioned the fact that he is third comedian I've heard this year doing a gag about selling his flat with the punchline a variant of "my landlord was furious". This prompted a reply on thisislondon.co.uk saying that Vine has often been a victim of gag-theft.

Now I wasn't for a moment saying that the other comics who had done this joke had lifted this gag from Vine. I was merely observing how certain gags seem to pop up more than once and when you go to as many comedy gigs as I do you can't avoid this sort of repetition. American Reg Hunter and Aussie Tim Minchin also shared a very un-PC gag about illegal mini-cabs and rape victims in Edinburgh this summer. Comic minds often simply think alike even when it comes to bad taste.

In fact you don't need to go to gigs to experience this kind of deja-vu. Last year when the Pope died I suggested to my long-suffering other half that the Vatican should get up to date and do a reality show to choose a successor – they could call it Pope Idol. Soon after that a letter in the Observer made the same suggestion. And around the same time – again, I'm not suggesting anything remotely light-fingered – Peter Kay brought the house down with a similar thought at the Royal Albert Hall. Some news stories are just begging to be turned into gags.

Back in the old music hall days it was common practice for acts to share material. Before the advent of television it was not unheard of for one comic to do the northern clubs and another to work the circuit south of Watford with exactly the same jokes. Television put a stop to that, and also created a voracious appetite for new material, which has kept teams of writers in regular work ever since.

The most bizarre thing about accusations of plagiarism is that sometimes not even death can stop them. A few years ago a website listed some classic Tommy Cooper gags, such as: "So I went to the dentist. He said 'say aaah'. I said 'why?' He said ‘because my dog's died.'" This, along with various other gags, had been credited to Cooper but had been coined by Tim Vine. A correction was later added. If you want to know how it feels to have your gags borrowed by someone who has been dead for two decades ask Tim Vine.