Lucy Punch

"So, let me guess - obesity and OCD right?" "She's a cleaner." Jack Armstrong (Toby Stephens) bulldozes through tonight's case set in a Priory-style rehab clinic with all the charm of an 80s cop who's found himself on duty in 2010 - a kind of posh, reverse Gene Hunt. It feels slightly stretched to fill an hour, but there's a lot to enjoy here, especially Kate's (Lucy Punch) awkward marriage counselling session.

"I'm trying to build a rapport here!" barks Jack (Toby Stephens) at Kate (Lucy Punch) in comedy-drama Vexed. Well let me tell you now, Jack, it's never going to happen.

Stephens and Punch play mismatched police detectives and for the whole of the first episode there wasn't any discernible chemistry, sexual or comic, between them. They drive around a lot, swapping snappy dialogue and engaging in frisson-packed narky exchanges, but for all the good it does their on-screen relationship they may as well have shouted it out of the car window.

It is never helpful to apportion blame, but it's Toby Stephens' fault. He just hasn't the lightness of touch to do this sort of comedy. His character, clearly intended as a cynical, manipulative but loveable charmer, comes over as an unpleasant oaf, pure and simple.

Lucy Punch, however, is as good as Stephens is bad. She makes Kate likeable, vulnerable, funny and very sexy. But even the sharpest flint can't spark off wet wood.

Well, it's all very well having these brilliant detectives, like Sherlock Holmes and Hercule Poirot and the CSI boffins, all going round smugly knowing everything and solving stuff. Obviously, if you were actually to be the victim of a crime, that's who you'd want investigating, or at the very least diligent, efficient plodders like the police in Taggart. But what about the rest of them, the rubbish cops who don't always get their man and don't have genius-level insights merely by looking at a few stray hairs or a misplaced receipt - aren't they being a bit discriminated against by TV?

Well, that gap is somewhat filled this week with a new comedy drama, Vexed, which boasts a crime-solving duo who won't bamboozle anyone with the cleverness of their deductions. A sort of cross between Moonlighting - the classic 1980s fantasy with Bruce Willis and Cybill Shepherd - and Jasper Carrot's spoof The Detectives, Vexed is a rather entertaining twist on the over-done crime genre.

It stars Toby Stephens and Lucy Punch - no, you'll recognise her, she's been in heaps of low-key British programmes including the more traditional detecting of Poirot and Midsomer Murders, but this is her biggest role so far as Lucy. But it's Stephens who is the revelation, taking a break from playing posh cads to revel in the role of Jack, who thinks he is a smooth charmer and great cop... when in fact, he's so useless he can't remember the names of anyone involved in the investigation (at one point he wonders if the victim was 'Andrew Ridgely' only to be informed that he's thinking of Wham!) and is prone to falling off his chair in the middle of interrogations.

Stephens' performance is great fun and a refreshing change from know-it-all detectives; Jack knows nothing, but is convinced that his instincts are right. "We're police officers," he drawls, "the law doesn't apply to us." Punch's role is to keep him in line and restrain her partner's more outrageous antics but, thankfully, she does get to be funny too.

The plot of this first episode is appropriately silly - about murders linked to a supermarket loyalty card scheme database, which distracts Lucy and Jack into using the info on it to sneak on what her ex and his potential partners are buying. And the comedy elements work better than the drama: it's hard to get really concerned about a dangerous situation when you know that there are not going to be any serious ramifications. So I'm not sure how long the series can sustain its freshness but it's a nice alternative for now.

Peppered with old jokes and a creaky soundtrack, it's a satire on 1980s sleuthing that plays its cards close to its chest, throwing in random old pop culture references in the middle of tasteless corpse-hopping. It may be giving it too much credit but it's deliberately rubbish, although not in a 'crikey aren't we clever at being rubbish?' kind of way.

Toby Stephens veers oddly over the top as DI Jack Armstrong, a character who could have wandered in from the first series of Life On Mars, but his partnership with Lucy Punch hit my wacky offbeat charm button. And what's not to love about a show where the kitten is called Keith?

Transposing the Lethal Weapon template to suburban west London, the rather too knowing Vexed teams Toby Stephens and Lucy Punch as mismatched, bickering detectives. The pace, be warned, is frantic to the point of being exhausting as writer Howard Overman takes the scattergun approach to gags and quips. Get past this, though, and Vexed is actually quite promising, largely because it works so hard to come up with original scenarios. The opener deals with murders related to a supermarket loyalty scheme.

It is always suspicious when the BBC tries to sneak out a new high-profile series with a star cast in the middle of August, while many people are away. In the case of this comedy drama, the suspicion is well-founded. Toby Stephens plays Jack, a cocksure womaniser of a detective, paired with Kate (Lucy Punch), a no-nonsense blonde. The two solve crimes while trying to sort out their own personal lives and bantering with each other. There are very few laughs.