review Thomas Sutcliffe

The current season of French and Saunders (BBC1) has depended heavily on film pastiche - last night, for example, opened with a spaghetti- western sequence, lovingly recreated on some Home Counties dude ranch, and previous episodes have included generously budgeted imitations of Braveheart, Batman and La Dolce Vita. Reduced to their elements, there is only one joke to these spoofs - the combination of painstaking pastiche and those moments when the two break out of character to bicker about each other's performance.

In fact, "out of character" is wrong, since what we see in these gaps is the created persona of the double-act - Saunders starchy and short-tempered (the grown-up), French skittish and apologetic (the teenager). This one joke will go quite a long way, given that they're both good comic actors, but it is impossible not to register the disproportion between the amount of money spent and the comic payload delivered. The sequences are often immaculate - beautifully designed, perfectly shot, wittily scored - but you can't shake the feeling that they are up there simply for your admiring inspection, as an exercise in style. They don't, for example, have much to say about the genres they mock, except that they can all be made to look ridiculous if you don't take them seriously - which is the starting point for parody, not really a fitting conclusion.

A flip way of putting one's anxiety about the series might be to say that it presents a case of wit stifled by money, except that in among the admirable longueurs of the series (you never quite want to go anywhere else while these things are unwinding) there have been sketches that worked in a different way and with absolute economy of means.

Last night included a nicely observed piece in which two romance-addicted women planned a joint wedding. There was a sort of punch line - the revelation that neither of the women even had a boyfriend, though their nuptials had been planned with sickly exactitude, from the playing of "Lady in Red" during the register signing, to the carpet of yellow roses leading up to the church. But the real pleasure of the thing was in the way it spiked the business of matrimony, the commercial encouragement to bet your entire emotional bankroll on the outcome of a single day.

Even sharper was the sketch last week, in which two over-anxious mothers took their infants through a hellish day of "quality time", intervening with an outraged shriek at every moment of childish spontaneity. This was so shamingly exact, so precise in its details, that it was worth sitting through any number of over-extended spoofs - such as last night's mystifying hybrid of Star Trek and the OJ Simpson trial - to relish its acuteness. French and Saunders are perfectly watchable rich, but they are unmissable poor.

Traces of Guilt (BBC2), an interesting series about advances in forensic science, suggested an answer to holiday laundry misery, that dismaying transformation of fresh garments into stale hamster bedding. In a reconstruction, last night's programme showed a forensic scientist obligingly washing out the smalls of Chen, a newly arrived passenger from Bolivia. The service is free, but has some drawbacks: the waiting room is Brixton Prison and it may take you months to get your washing back.

In Chen's case, six kilograms of cocaine were recovered from the final rinse, a definite result for the customs officer who had first sniffed suspiciously at his underwear. The strength of the series, though, is that it goes beyond the complacent triumphalism of previous forensic programmes - showing that technological ingenuity may help us to describe a crime more exactly, without greatly improving our chances of preventing it or delivering justice. Run this series through a gas chromatograph and you would detect more than just a pinch of salt.