Television review

I've steered clear of The Thin Blue Line (BBC1) for a few weeks, largely for fear of making an unjust arrest. The first episode looked like an open and shut case - a smash and grab raid on an antique joke shop, with the swag carried away in a stolen vehicle officially registered to Jimmy Perry and David Croft. Then again, the chief suspect had "previous", as we say in the force, and it was all in his favour. So it seemed only fair to give Ben Elton the benefit of the doubt and wait for a bit more evidence to mount up.

Three weeks on things aren't much easier, though it has at least become indisputable that, if this is a crime, it is of the copycat variety. Elton has taken the comic structure of Dad's Army and given it a quick paint- job - the Mainwaring figure is Inspector Fowler and there is an almost exact equivalent of Bill Pertwee's air-raid warden in Detective Constable Kray, a boorish CID man who engages Fowler in petty skirmishes over authority. There's also a Private Pike equivalent in PC Goody, a gurning twit who is the small screen's least convincing heterosexual since Kenneth Williams laid siege to Hattie Jacques (James Dreyfus, who plays Goody, also seems to have been elected to go over the top on behalf of the entire cast).

The result is decidedly uneven at times, changing its registers in an unnerving way. At one moment, this is the sort of sitcom in which a reference to "delicate operations" will automatically lead to a conversation about bowels, the sort of sitcom in which dialogue is levered into place so that a conversation about a quiz game can be misinterpreted as evidence of sexual infidelity ("I didn't expect such a hard one"). At the next, it delivers a much more subtle comedy of character - the prolix DC Kray ends a nicely observed bit of macho blather with the urgent reminder that "it's my backside on the line and I'm up to my neck in it". Last night's episode opened with a good gag too, in which the inebriated Fowler, returning late from a night out at the pub, tries to win over his girlfriend. "I've been buying you a present," he says, with the enfeebled inspiration of the authentic drunk. "What is it?" she demands icily. "A kebab," replies Fowler, holding out a limp pitta with wobbly pride.

Atkinson does this justice - it needs an expression of woozy idiocy to pull it off - but he has to save far more gags by his delivery. More frequently than is healthy, a belly laugh is followed by a groan at the creaking machinery of the comedy. Matters aren't made easier for Atkinson by the fact that his character also changes from scene to scene, sometimes irretrievably ridic-ulous and the next moment capable of an aria of agile scorn, worthy of the great Blackadder himself. Still, that very comparison is a reminder that the first series of Blackadder was a pale shadow of what it was to become - which suggests we should merely keep The Thin Blue Line under close surveillance for the time being.

The smell of a rose, we learnt in Horizon's "A Code in the Nose" (BBC2), is composed of around 200 different molecules. But nobody quite knows how the brain finds out which molecules have drifted in through the nostrils. For some time the prevailing theory has been that of locks and keys, the idea that the molecules fit into precisely shaped receptors inside the nose. Luca Turin, who teaches bio-physics and collects fragrances, has a different theory - that the nose recognises molecular vibrations. There is a philosophical difficulty here - one of the indispensable pieces of equipment in testing any theory of smell is the nose, a suggestible organ which also happens to be the subject of the experiment. Isabelle Rosin explored this and other scientific niceties and also concluded with a real coup, a sequence in which three top perfumiers confirmed that Turin had been able to predictably engineer one smell into another. Turin's principle theoretical opponent looked as if he'd smelled a rat.