"Most people think they must be easy to write because the ones they see are often not that good. In fact they're not that good because they're bloody difficult," says a BBC script editor, who reveals that the BBC receives around 3,000 scripts every year from people tackling this most deceptively difficult of screenwriting disciplines. And they read every single effort.
What makes one stand out?
"Apart from professional presentation, there are four main constituents to a sitcom. The idea, the characters, the story and the dialogue. Get those right, in the right order, and you're well on the way."
So what ideas, and what characters, are the BBC and their commercial counterparts after?
"We'd like to see more originality," says the man from the Beeb helpfully. "At the moment, every other script features someone who is Victor Meldrew in all but name. New writers are surprisingly unadventurous."
New writers, of course, are of the opinion that this reflects the wariness of the BBC, or anyone else, to try anything new. As Catch-22 chestnuts go, this one is as old as the Beverly Hillbillies.
A quick survey of script editors produces a few pointers of things they don't want to see:
Sitcoms set in dating agencies, stripogram offices and (bizarrely) look- alike agencies are arriving all the time.
Sitcoms in which there are a whole bunch of people cracking jokes. These break two rules. Firstly, people generally like there to be one, or at most two, main characters. Even in ensemble pieces (eg Dad's Army) there has to be a rigid hierarchy. Few shows in which the focus changes from week to week succeed .
The British generally prefer to watch characters who are oblivious to their own absurdity (eg Captain Mainwaring) than characters who think they are funny.
Even in American sitcoms like Frazier and Seinfeld, where the main characters happily wisecrack their way through the entire show, the best laughs always come at their expense, not at their behest.
If you are thinking of writing a sitcom along these lines, incidentally, it is worth noting that in America, team-writing is the norm. This involves large groups of highly-paid people being employed to cram as many funny lines into a 22-minute script as is humanly possible.
Writing accounts for 30 per cent of production costs in the States as opposed to eight per cent over here and there are no prizes for guessing whose budgets are bigger to begin with. Hardly surprising, then, that US comedy is more gag-intensive.
When you do insert a gag, says the BBC script editor, it shouldn't tickle your audience, but wind them. Not for nothing are they called punch-lines. "We get too many amusing scripts. We want funny scripts."
Of course, being funny is the whole trick, but there are a few simple stratagems that can help. For instance, putting the funny word at the end of the line, rather than in the middle, leaving a natural pause for the audience to laugh. Obvious, you might think, but often missed.
To learn a few more tricks of the trade, keep in touch with courses, bursaries, competitions and the like, and generally kid yourself that you're on the way, join the London Screenwriters Workshop. Despite the name, they have a large non-London-based membership, organise inexpensive courses, and it only costs pounds 25 a year to join. You even get membership of a London club with a late bar.
Please send all further queries to them - but not to the BBC who are quite busy enough with this week's skip-load of unsolicited scripts, with their funny words in the wrong places.
London Screenwriter's Workshop, 84 Wardour St, London W1V 3LF (0171- 434 0942). Send scripts to Comedy Development Unit, BBC TV Centre, London W12 7RJReuse content