Last Night's TV - Whitechapel, ITV1; A History of Horror with Mark Gatiss, BBC4

Whatever happened to cops and robbers? They've been replaced by cops and slashers, cops and nutters, cops and perverts. Hardly any TV detective gets through a day's work without viewing at least one mutilated body. Goodness knows what they'd have made of it all down at Dock Green police station.

I can understand that the kind of wrong-doing that occupied dear old Sergeant Dixon wouldn't hold the interest of a modern primetime audience, but surely we haven't become so bloodthirsty that we would deny our fictional crimebusters a spot of grand larceny to deal with for a change, maybe a nice fraud or embezzlement case, with no tortured bodies washed up on the banks of the Thames, no battered corpses found in basements. Or have we? Maybe we get the crime dramas we deserve.

Whatever, scarcely had Stephen Tompkinson as tall maverick cop DCI Banks solved the case of a serial killer than here comes Rupert Penry-Jones as tall maverick cop DI Chandler, wrestling with some more grisly goings-on in Whitechapel. It must have seemed like a smart idea to call a cop show Whitechapel. Normally, titles are all about the cop: Inspector Morse, Bergerac, A Touch of Frost, Dalziel and Pascoe. But here's one that evokes a place, a real place associated with nasty men such as Jack the Ripper and the Kray twins. You can almost hear the brainstorming session over skinny decaf lattes in a Soho production house: "Hey, let's make the star of the show an area, not a person! Can someone pass the nutmeg?"

There is a problem with the name Whitechapel, though, albeit of the production team's own making. The first series had DI Chandler and his team searching for a copycat Jack the Ripper, and now they're looking for a copycat Ronnie and Reggie Kray. Or maybe it's twin copycats, we're not sure yet. Either way, what I sniff here is copycat drama, and it makes me fret for the next series, because if all the storylines are to refer to people and events Whitechapel is already famous for, then DI Chandler might just find himself investigating a copycat Tracey Emin exhibition at the Whitechapel Gallery, or possibly a copycat salt-beef sandwich at a copycat Bloom's restaurant on Whitechapel Road.

For now, though, it's the Krays, and we'll overlook the inconvenient fact that their manor was more Bethnal Green than Whitechapel. Besides, it was at the Blind Beggar pub in Whitechapel Road that Ronnie killed George Cornell of the Richardson gang, supposedly while "The Sun Ain't Gonna Shine Any More" was playing on the juke box. I know that because I was once given a personal gangland tour by Cornell's associate "Mad" Frankie Fraser, and the Blind Beggar was where I made him an offer he couldn't refuse and bought him a cheese and pickle bap.

Anyway, back to Whitechapel, in which someone is going round the neighbourhood razoring people, having formed a kind of Kray tribute act – Tjorn Again, if you will. Even worse, the villain is replicating the notorious Kray murders, so DI Chandler has his hands full.

These, you will recall from series one, are notably spotless hands. Chandler is a cleanliness freak, and quite possibly the most prissy, precious and indeed polite cop in TV history, making Hercule Poirot look like Taggart. The lovely improbability of this just about sustained me through the first series, but there comes a point at which it all gets so silly that you have to start viewing it as comedy. I reached that point about halfway through last night's episode. By the time DCI Cazenove (Peter Serafinowicz) administered a brutal beating to one of his detectives, I was doubled up no less than the hapless victim. The credibility of the thing, like old George Cornell, was shot.

Still, it's not just for the unwitting laughs that make Whitechapel worth following. Phil Davis is as watchable as ever as the embittered, seen-it-all Sergeant Miles, and I like Steve Pemberton's hammy turn as an amateur sleuth, who once again is three steps ahead of the professionals. Pemberton is a graduate of The League of Gentlemen and it was a good night for former inhabitants of Royston Vasey, because A History of Horror with Mark Gatiss was terrific, even for those of us who don't much care for the genre.

When actors present documentaries, their enthusiasm for the subject all too often seems manufactured. But Gatiss really, really loves horror films, and always has done. The best Christmas present he was ever given, he admitted, was a book called The Movie Treasury: Horror Movies. He was only eight, an age when most children prefer Disney cartoons, and coincidentally one of the marvellous titbits that this programme threw up was that Donnie Dunagan, the child actor menaced by Boris Karloff in Son of Frankenstein, later provided the voice of Bambi.

Gatiss interviewed Dunagan, and several other veterans of Hollywood horror, among them Carla Laemmle, the 100-year-old niece of Carl Laemmle who founded Universal Pictures. Carla even remembered her opening lines from Dracula (1931), which was the first horror picture with sound, and was directed by Carl Laemmle Jr. As someone once said, the Laemmles liked to keep it in the faemmle.

But as I say, I've never been a fan of horror films. And who needs them anyway, when every police procedural is a horror film writ small?