I come up with a gag and find out later someone else has written more or less the same joke
Recently I was a guest on one of the new and exciting, mould- breaking talk radio programmes that are now being made by independent production companies for BBC Radio 4 as part of the network's enforced quota of outside programming.

The trouble with trying to be new and exciting, etc, in the talk radio game is that all the shows are, by definition, just people yakking at each other - so the search for new formats, new contexts in which to put the people yakking at each other, can become somewhat desperate.

The show I was appearing on was a perfect example of this desperation. It was called In The Dentist's Chair. Each week a celebrity is interviewed by Professor Tom Kermode, Fellow of the Royal Society of Orthodontists, LDS, RDS (Eng). As he performs major bridge work or replaces damaged crowns, Professor Kermode asks his guest of the week searching, profound questions of deep philosophical, aesthetic and social importance.

"Do you agree?" he asks, "that Constructivism opposed the contemporary movement of Expressionist thought in promotion of the reasoned deployment of the principles of 'pure art'?" And the guest replies, "Mghh maag grumgh waa." The fee for appearing on this show is pounds 75, new fillings and a sugar- free wollypop.

While I was waiting in the reception room of the radio production dentistry company, I began idly to flip through a copy of Broadcast - one of the entertainment industry trade papers. Among the showbiz news, it always gives information on the performances of films at the UK and US box office, and I happened to notice that the Highland epic Rob Roy, starring Liam Neeson as a be-kilted noble Celtic fighter combating decadent English oppression, had taken $30m at US cinemas in its first week. I thought this was not only very good going, but that that kind of success must have completely stuffed up the chances of the movie Braveheart, due to open a few weeks later and starring Mel Gibson as a be-kilted, noble Celtic fighter combating decadent English etc, etc.

That two films with almost identical themes and locations should come on to the market more or less simultaneously is not, perhaps surprisingly, such an unusual occurrence. In fact, it happens most years.

In 1994, the cinemas were briefly full of a whole stew of Wyatt Earp movies, including Kurt Russell's Tombstone and Kevin Costner's Wyatt Earp. In this case, having several revisionist westerns to choose from, when one would have been more than enough, completely stuffed up the chances of all the new-wave cowboy films concerned. And when The Madness of King George burst on to the US market, the producers of another very similar movie, The Mild Depression of the Duke of Windsor, were thrown into a panic as they were due to open a month later. However, they managed to collect themselves and, with the addition of hastily re-shot scenes, successfully turned their film into a kung fu flick complete with a high- kicking Ninja Wallis Simpson.

Another two films that almost mirrored each other were the mystical sword fight movie Highlander - about a Scotsman who lives for ever - and a smaller budget British film called Midlander, which was about an Aston Villa supporter from Perry Bar who lives for ever. Actually, the Brummie was not immortal, but watching an Aston Villa game, it just seems like it lasts for ever.

But why do all these identical films appear at the same time? Well, part of this can be explained by the entertainment industry's nerd instinct. If the feeling goes around that Scottish epics or Ninja Duchess of Windsor films are the hot ticket, then 10 will go into production immediately. But perhaps there is more to it than that.

As a joke writer, I have noticed that time and time again I will come up with a gag and I will find out later that somebody else has written more or less the same joke. The explanation perhaps is that the idea, the central core of the joke, is just sort of "out there": that somehow a concept created from a thousand different events and thoughts can hang in the air, waiting to be plucked by desperate comedy writers straining at their word processors.

Either that or they have nicked the gag off me or I have nicked the gag off them and I am pretending to myself that they have nicked the gag off me.

Certainly the lengths to which comedians will go to disguise the authorship of a bit of material are vast. WC Fields used to steal routines from other comedians; then, when he saw them performing what he thought was now "his" sketch, would beat them up.

So, if you see an almost identical article to this in another newspaper, I almost certainly definitely thought of it first.