The Weekend's TV: Scott &amp; Bailey, Sun, ITV1<br/>Paul Merton's Birth of Hollywood, Fri, BBC2

Worthy of further investigation

"Let's see," you can imagine ITV's commissioning editors saying to themselves a year or so ago, "What can we do to refresh Sunday nights? Wouldn't it be great to have something different, something that hasn't been done before?

No country vets, no murders, no doctors and nurses." Perhaps ideas were floated. A drama about a young internet entrepreneur, maybe, or a hotelier or a probate researcher. What about a six-part series about a Northern club entertainer or local radio shock jock with a bad habit of getting involved with his callers? Or a comedy-drama set in a failing Blackpool nightclub run by a psychic drag queen? Before them an ocean of narrative possibilities spread wide, with innumerable routes as yet unsailed. And then someone said "No, sod it... it's too risky. Let's do another cop show."

Scott & Bailey is the result of that less-than-courageous decision. And, in fairness, one should probably acknowledge that – as dispiritingly spineless safety plays go – it isn't all that bad. It has Suranne Jones and Lesley Sharp in it for one thing – actresses who could probably even give a bit of human depth to a DFS Half Price Sale ad. For another thing it's written by Sally Wainwright, who's shown an ability in the past to give the most hackneyed television forms a little bit of verbal topspin. And there's also some promise in the continuing storyline, that portion of the script that holds each week's one-off stories together like the plastic necklace on a six-pack of beer.

Jones plays DC Rachel Bailey, dumped by her boyfriend in the opening moments of Episode One – and dumped with a string of flabby clichés that squarely mark him out as a dead loss. "I feel that I need more space at the moment," he tells her, which is a bit of a shock for Rachel because she thought the smart restaurant was the prelude to a proposal. Her boyfriend, it turns out, is somebody else's husband. And wouldn't you know it, the murder that lands on Rachel's desk the very next morning involves a husband who has been playing away. She has a hunch – that all men are bastards – and the chief suspect appears to offer corroborating evidence. Sharp plays her colleague DC Scott, who has to try and prevent Bailey's furious sense of personal victimhood from leaking messily into the investigation.

Cagney and Lacey they're not. Indeed, one of the heartening details is the vague sense that they aren't each other's best friend. Scott is married with children, while Bailey is suddenly painfully single, with nothing to do in her off-duty hours but harass the man who has humiliated her (a less than assiduous attendance to personal hygiene was one of the reasons he offered for their incompatibility). Access to the Police National Computer makes this a little easier than it would be for the average jiltee – and, in the teeth of Scott's disapproval, she starts to use her professional skills to work out where her errant boyfriend has gone, and what he's been hiding from her. Meanwhile, Scott has been approached by an old classmate who thinks she might be able to help with a cold case, the child murder that inspired her to join the police in the first place.

It was a little disappointing that the case was cracked by a coincidence so far-fetched that it made your eyes water (driving from Manchester to Leeds, Scott fortuitously stops off at the same petrol station used by the killer and then recognises the forecourt flowers that were left by the body. Because, of course, petrol-forecourt flowers are famous for their unique "fingerprint"). The guilty woman then crumbled under questioning with an implausibly lubricated ease. But when it isn't insulting your intelligence, there are genuine signs of life in the thing. "I'm not kidding Sammy," said the female DI at one point, getting heavy on the phone with an awkward customer, "I want you to take a photograph of your homework – completed – and text it to me."

Paul Merton's Birth of Hollywood, a three-part history of the early days of American cinema, began with the kinetoscope, reasonably described by Merton as "a primitive version of YouTube". Early viewers could watch boxing kittens (LOL), men showing off their muscles and a pair of male Edison company workers waltzing together while a third played the violin. "This experimental film," Merton explained drily, "was made before the invention of women." As it turned out there wasn't a great deal of that kind of thing, Merton's sincere enthusiasm for the silent era and its pioneers trumping his sense of humour. He directed as well – with a touch that wasn't always entirely sure. An idea would turn up, be tried out, and then disappear entirely – as with a couple of intriguing moments when we segued from Merton in the polychrome present to a monochrome reconstruction of historic filming methods. Full of interesting things, though, from the real New Jersey cliffs that gave the world the "cliffhanger" to the reminder that Wagner's "Ride of the Valkyries" got its first cinematic outing when it accompanied stirring footage of the Ku Klux Klan on the rampage, in D W Griffith's gruesomely racist The Birth of a Nation. And right at the end, more laughs – when you got the blooper outtakes from his pieces to camera. Next time round, though, I think Merton the director should insist that Merton the presenter loosens up and gets a bit more playful.