TELEVISION Murder Most Horrid / BBC2

In which our comedy heroine, Dawn French, tries hard to be just another comedy heroine. And, mercifully, fails

Read the review of any sitcom's first outing and the truism is almost always there. Too early to judge it ... hasn't had time to settle ... the characters are too busy telling you who they are to let you know what they're like ... should pick up in the second episode or, even better, the second series.

The half-hour comedy drama cannot fall back on the safety net of deferred assessment, because the characters have to convince you of their comic richness before the curtain comes down for ever. In "Girl Friday", the first story in a new series of Murder Most Horrid, Dawn French was at it immediately, not to mention literally. To the sound of squeaky panting, the camera pans across the mezzanine of a modest but tasteful loft until it locates the source of the noise. There on the bed in all her glory is Sally (French) having the life humped out of her by a lover whose face we never see. Sally is an obsessively efficient secretary to a suave bigwig in construction, and mid-coitus she gets the urge to call the office; her long-suffering partner pulls on his trousers and, undetected, walks out of her life. A wealth of information and entertainment has been impressively squeezed into no more than a minute of screen time.

So French doesn't get to be Beatrice Dalle in Betty Blue and achieve the orgasm which, from what we know of her screen personality, would probably not be a timorous affair. This is a good example of Horrid heroically refusing simply to play to the strengths of its star, in this case her sheer unfettered loudness. But pretty soon the script has given in. At work, Sally toes the line in the morning but, nursing an unrequited crush for her boss, has long liquid lunchbreaks and comes back to the office pulling funny faces, rolling her eyes and running through the comic business that French can't resist. When she smacks into a glass door, there's a real sense of guilt as you laugh at such a hackneyed stunt.

In one scene, she's even doing hamming it up quite badly, but it turns out that her character is only acting drunk. There's quite a fine distinction between acting hammily and playing someone who's hammy as a pretence, but it's probably not something that Horrid spends much time dwelling on.

The plot is not a complicated thing either, as there are only so many twists you can coil into a half-hour thriller. The boss (Nigel Havers in full cad mode) knocks out his wife; Sally, the only witness, throttles her as he calls the ambulance, and they dump the body. She circuitously lands him in prison and then blackmails him all the way to the altar.

Paul Smith's script has some nice touches. There's some dialogue in Dutch for French, a reference to afternoon rates at the thinly disguised "Lanesbrook" hotel, and French is given a line she was born to deliver but somehow never quite did to Jennifer Saunders. "Tell me I don't look a day over 25 and I'll sit on your knob all night." To make an offer like that takes real balls.