The newest thing in comedy sketch shows - and doesn't that very phrase feel antediluvian? - is Watson & Oliver, well known to Edinburgh Fringe audiences. They're an appealing duo. Ingrid Oliver has a thrillingly low voice - Fiona Bruce meets Victoria Coren - she's a dead ringer for Myleene Klass (who is duly ridiculed), and she can really act. Lorna Watson is blond, brittle and has to work harder for laughs. Their opening gambit was a direly old-fashioned bit of sub-Morecambe & Wise before-the-show backchat, but, once they settled down, their sketches were inventive and unusual. In a spoof of a TV Jane Austen serial, the mob-capped duo tittered like six-year-olds about pin cushions to a pair of bored Mr Darcys, then switched abruptly to double entendre. ("Our dance cards - we eagerly await the filling of our slots by two special gentlemen.") A Victoria Wood-style pastiche of 1950s ladies' kitchen conversation - all pinnies and hair-rollers - was surreally punctuated by Watson's response-appropriate eyebrows. A greasy-spoon café became a symphony of shouts and orders in which everyone called everyone else "darling" - "Cup o'tea, darlin'?" "Keep the change, my darlin'" - until someone silenced the room by saying "Love". In what is clearly meant to be the show's signature sketch, the girls do their impression of Prince William and Kate tucked up in bed, unable to find anything to talk about except their wedding day. But couldn't they have found a better punchline subject than Pippa Middleton's over-prodded rump?

The best sketch imagined two Playboy bunnies squeaking competitively about how pink their living quarters were, how appealing their fake boobs, how delightful their lives, until they were summoned to cuddle up to the saurian Hefner. Between retchings, they competed as to which had a better excuse not to fulfil this noisome duty. It was a gift of a subject to these two funny, appealing women, and they seized it with unladylike glee. I look forward to seeing a lot more of them.

New sketch comedies have been so mediocre recently that the format itself has sometimes looked on its last legs. However, portents for this new show are good. For a start, Robert Popper is producing. Also, it's been dropped straight into the BBC2 schedules without the customary trial period on BBC3/4, which indicates a certain assurance. Sadly, this confidence seems misplaced. Lorna Watson and Ingrid Oliver have good chemistry, but the scripts and ideas remain resolutely earthbound. There's a sketch lampooning mannered costume dramas. An extended, tedious musical turn from John Barrowman. A sketch about the enduring hilarity of working-class people's vocabulary and speech patterns. But nothing to suggest that Watson and Oliver might buck the trend.

Having hoovered up several comedy awards with their stage act, Watson & Oliver have been entrusted with their own BBC2 sketch show and the initial results are encouraging.

Do not expect any comedy revolution as their approach is remorselessly mainstream, inevitably inviting comparison with French And Saunders - did I mention that Watson and Oliver are women? However, the material is genuinely funny and the performances winning. Allowing for the fact all sketch shows are inherently inconsistent I'd say their first episode registered around a 75% success rate, which is good.

They also deserve credit for a particularly high-risk finale, which saw the pair fight for the right to share a show-stopping duet with guest star John Barrowman. All teeth, jazz hands and unconfined ego, Barrowman sent himself up with an enthusiasm that threatened to overwhelm his hosts, but they weathered the storm of upstaging intact.

It only remains to be seen if Watson & Oliver will fall prey to the dominant trend among sketch shows of lazily recycling the same gags and characters, albeit with minor modifications, throughout the remainder of the series.

Watson & Oliver, BBC Two

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The BBC evidently have faith in Lorna and Ingrid, they've already been awarded them a six-part series in a shiny prime spot on BBC Two and a whole host of celebrity guests, but it all feels vastly premature.

Watson & Oliver: Bring out the Barrowman

Lorna Watson and Ingrid Oliver's new comedy sketch show is a peculiarly old-fashioned thing.

Watson & Oliver review

Sketch comedy by its very nature is hit and miss, and in this opener Watson & Oliver had only one dud (the point of the Barrowman gag, where they vied for his attentions, was a little too predictable) but the quality of the other sketches more than made up for that. A hit, a palpable hit.

Are Lorna Watson and Ingrid Oliver poised to become the next French and Saunders?

They've got the talent and are both immensely likeable, but what they're lacking right now is better material.

There's nothing in the first outing for their new sketch show to dislike, but nothing that really stakes out new comedy ground for female comedians in the way that Smack The Pony or Catherine Tate did. A take-off of Kate and Wills capitalises on Ingrid Oliver's passing resemblance to Kate, but doesn't really know where it's going.

What's most worrying is that they deliberately let their guest star John Barrowman steal all their laughs as well.

Eric and Ernie might have used stage stars to their ­advantage, but Watson and Oliver are a long way from being Morecambe and Wise.

We're not writing them off yet - we're just saying they should write off their writers and get some new ones.

The Beeb's new comedy signing is about as edgy as Lorraine Kelly's guide to budget family dinners. There's more than a whiff of nostalgia in Lorna Watson and Ingrid Oliver's debut comedy sketch show, and if you long for the cheekily innocent days of French & Saunders, Watson & Oliver looks set to satisfy that itch. Expect period drama pastiche, Wills and Kate jokes, and live studio audience laughter aplenty.

It would be so easy to shoot this sketch show by a couple of relatively unknown comedians, Lorna Watson and Ingrid Oliver, right out of the water. I could say that on the whole it's pretty poor, with a few thin laughs in a clutch of woefully under-written sketches. I could say that Watson & Oliver must have known it was in trouble when it gave a substantial guest spot here to John Barrowman playing a preening, narcissistic version of himself.

I could add that with a lot more work Watson & Oliver might find themselves a niche on television after a successful live-performance career. I could say all of these things. But I won't.