Exile, BBC1, Sunday, Monday, Tuesday<br/>The Shadow Line, BBC2, Thursday<br/>Psychoville, BBC2, Thursday

There was a lot of banging going on in Auntie's three-part thriller Exile, thanks to John Simm as coked-up, beat-down journalist Tom Ronstadt.

First he was banging on various windows as he was frogmarched from the offices of a magazine from which he'd just been fired. It looked a bit like a lad's mag, possibly a gossip rag; in any case, it was one that somehow paid him enough that he could afford the flash car that muscled him back up north. And within five minutes of arriving home in the town he'd left 18 years earlier, he was banging again, though this time it was the local barmaid, Mandy, who was the object of his exertions – the first of rather too many plot contrivances in too little time.

For it turns out that Mandy was the wife of an old pal of Tom's, who in turn worked for the head of the local council; and this councillor had once been a doctor, at a psychiatric institution, whom Tom's father, Sam, played by Jim Broadbent, had been investigating as a reporter. And it was this investigation that had led Tom to flee home: Sam had beaten him half to death after catching him scrabbling through his research.

After three hours of fraught drama, we learnt that Tom was not actually the son of Sam, but rather of a rapist who had been an orderly at the hospital; Sam's wife, now dead, had been given baby Tom as a bribe to stop her husband from spilling the beans that the doctor was encouraging the rapes and selling off the babies.

Exile's creator, Paul Abbott, can do conspiracy – 2003's State of Play was outstanding. But these coincidences felt forced, perhaps because they didn't have enough time in three one-hour slots to feel natural; and the ending was surprisingly flat. More to the point, it all felt an adjunct to the far more involving domestic drama centred on the Ronstadts.

Broadbent was exceptional as the Alzheimer's-afflicted Sam; an actor's eyes have rarely told more – there one minute, gone the next, he was utterly believable. And the effect his dementia was having on his daughter, played by the terrific Olivia Colman, and upon Simm – seen most forcefully in a compelling scene in which son tried to drown father – was mesmerising. And it was these fractured bonds – rather than the somersaults of the plot – that made Exile worth watching.

The Beeb's other thriller of the week, The Shadow Line, was anything but rushed. In fact, this epic seven-parter with a star-studded cast looks like being a real slow-burner; even the opening scene, of two policemen measuring up a corpse, was deliberately drawn out.

That dead man was Harvey Wratten, a drugs baron recently let out of prison, having been given a royal pardon. And why would a drug dealer be given a pardon? Must be a rat ...

Thus are we drawn into a world where no one's on the up and up – not even our (anti-)hero, played by Chiwetel Ejiofor, who presumably has a good reason for having a bullet in his brain as Jonah Gabriel (for goodness' sake, do we really need such obviously indicatory names?) other than just giving people something to say about him. Because until he turned out to have a briefcase of money stashed in his wardrobe, he seemed pretty dull.

As for Rafe Spall, who plays Wratten's allegedly psychotic nephew – with his silly little grin, he displayed all the threat of a mewling kitten. Still, onwards and upwards – and I at least will be tuning in for the next episode, if only to watch the machinations of Christopher Eccleston as the venerable Joseph Bede. (Seriously, enough of the symbolic nomenclature.)

For a monster rather scarier than Spall's Jay Wratten, we needed look only to the following half-hour on BBC2. Reece Shearsmith's Silent Singer, a newcomer to Psychoville, is genuinely terrifying. And all he did was make jerky movements with his upper body while standing still. There was something about those pigtails, though ...

From killer lines ("You made it, then?" Mr Jelly remarked to a fellow survivor of the fireball that seemingly engulfed the entire cast at the end of series one. "Yeah, got the train," came the perfect answer) to a killer on the loose, every second of this pitch-perfect dark comedy is a joy. Albeit a joy perhaps best watched while cowering behind the sofa.