Laura Solon, Radio 4<br />Double Science, Radio 4<br />The Unbelievable Truth, Radio 4

Comedy so short of laughs it wipes a smile off the face of the earth

Regular readers will know that this is a theme I return to again and again. But it is important. Just as Cicero went through a phase where he used to begin every speech to the senate with the line "Carthage must be destroyed", so I have to say, far more often than I would like: Radio 4's comedy output needs a really big overhaul.

There are programmes that ring their own leper-bells, so you know you can avoid them. An all too typical example is Laura Solon: Talking and Not Talking, which goes out at 11.30pm on Wednesdays. The description given on the BBC's iPlayer includes the words "packed with bittersweet character monologues and cuttingly modern sketches", which is another way, as even the most cursorily experienced listener will recognise, of saying "not very funny". It illustrates the inverse formula given by Tolstoy about happy and unhappy families: all funny radio sketch shows are funny in different ways, but all unfunny ones are unfunny in the same way. I mean, how many different ways are there of being unfunny?

With marginally more potential, but not much more success, is DoubleScience (Wednesdays, 6.30pm), "a sitcom about two incompetent science teachers who work at a college that specialises in drama". "Incompetent" could fit the bill, in that one of the science teachers concerned, looking at a new poster of the periodic table, observes that radon sounds like something you'd put in your washing machine. But never mind the marginal desirability of putting this weak joke in the script at all, how likely is it that a science teacher, however incompetent, would say such a thing?

Here is the sport the show makes about the teachers: they like real ale; they play Dungeons and Dragons; they are unsuccessful with women; they have undesirable living quarters; and they speak in comedy voices, one a bit like Neil from The Young Ones and the other like John Major. There is, for good measure, the proprietor of an Indian restaurant who addresses his clientele as "gentlemens".

By fluke rather than by design, my children and I have listened to the last two of these shows. Last week, the eldest, who until then had been in quite a sunny mood, suddenly lost all her joie de vivre and said, "Is this the one that's supposed to be funny but isn't?" "Let's give it a chance," I said. Thirty laugh-free minutes later, the children were looking defeated and mistrustful.

Also conceptually problematic is The Unbelievable Truth which, thanks to presenter David Mitchell and the calibre of many of the guests (Graeme Garden, Tony Hawks), cannot fail to raise a laugh from time to time; but the very format of the show, which is too boring to write out, means that contestants are too busy paying attention to the others' flights of fancy to fabricate jokes. Its format is also a regression from the principles of I'm Sorry, I Haven't a Clue, which was billed, you will recall, as "the antidote to panel games".

The funniest show on radio, then, for the last few weeks, has been David Quantick's The Blagger's Guide (Radio 2), whose run is now sadly over. But that's too music-oriented for Radio 4. So what's going wrong? It could be sod's law. Or a telescoped version of the seven years of plenty/seven years of famine deal. But the main problem is that no one at the station seems to be saying, even of the shows which go out at 11.30pm: "Do this again. It isn't funny enough yet." This can be done kindly and productively.