Southcliffe, Channel 4

The last time I noticed Sean Harris he was playing Micheletto Corella, the merciless assassin and enforcer for Pope Jeremy Irons and his Borgia clan. Unpleasantly good at it he was too.

Perhaps it would be unfair to describe his appearance in Southcliffe as typecasting, but you can hardly fail to spot some similarities. As Stephen Morton, whose robotic killing spree with his private collection of automatic weapons is the driver behind a group of interlocking stories set in the coastal town of Southcliffe, Harris projects a similar suppressed intensity and inner turmoil, as well as a staring-eyed aura of unnerving menace. Like Corella, he uses silence as a deadly weapon.  

It's a formidable performance, and it can't have been an easy one to give. Writer Tony Grisoni has piled on the misery by making ex-soldier Morton a freakish loner in the grip of militaristic fantasies, living in a small house where he cares for his bedridden, invalid mother. There's a suspicion that you may be supposed to feel the occasional twinge of sympathy for him, before he cracks up entirely and shoots mum, dog and a long list of other locals.

But really, isn't this just ITV's Broadchurch with a mass murderer instead of a child killer? Again we have a small, tightly-knit community in a seaside town (Southcliffe was filmed in Faversham, Kent), and a story which is as much about the effect of the murder(s) on a cross-section of local people as it is about the crime itself. Both series share an irritating fragmented structure, so you're often momentarily bamboozled as you try to find your place on the timeline.

The phenomenon we may term Southchurch, or perhaps Broadcliffe, also seems in thrall to the delusion that a gloomy backstory and lives blighted by secret sadnesses automatically mean human interest and great drama. It's more like screenwriting-by-numbers, and is merely bloody depressing rather than offering any revelations into the human psyche. So, Southcliffe gives plenty of space to the philandering pub landlord Paul (Anatol Yusef), who short-changes Morton for odd jobs around the house and is openly cheating on his wife with a student. He's an odious little slimeball, and no more sympathetic after having his wife and kids murdered offscreen.

Then there's the sombre tale of Claire and Andrew Salter (pictured above, with daughter Anna at right). Claire (Shirley Henderson) works for Social Services and helps look after Morton's mother, but is being driven into terminal depression by her failure to conceive a child. Husband Andrew (Eddie Marsan) works at the local power station, and seems very nice and stultifyingly boring.

We're going to see a lot more of Rory Kinnear, playing flashy metropolitan TV journalist David Whitehead (pictured left). He too appears to be playing away from the missus, but the Morton killings present him with a special problem because he grew up (unhappily, of course) in Southcliffe. We kept getting great flashing warnings about how meaningful this was. First of all Whitehead tried to defy his news editor and not get assigned to the story. Then, as he drove down to the coast, his assistant in the passenger seat got a phone call saying the killer was Stephen Morton.

"Stephen Morton?" said Whitehead, as metaphorical violins played a shivering minor chord.

"Mean anything to you?" his companion retorted.

(Very long pause, tragic expression): "Yes... I remember the name."

Frankly this is dreary stuff, and - I may have said this before - there's surely a pressing need for a moratorium on murderers and serial killers. There are alternatives -  there have been successful series in the past about things like lawyers, politicians, the Home Guard, psychotherapists, cowboys, the advertising business, paranormal investigators, undertakers, the garment industry... You have to wonder if our TV is suffering from a mystery virus which blights the imagination, a dry rot of the soul.