TELEVISION / Death throes: Andy Gill on The Execution Protocol, Gallowglass and Saturday Zoo

In a bout of perverse scheduling, BBC 2 chose Saturday evening to screen The Execution Protocol, an overlong and gruesomely detailed account of capital punishment provisions in the state of Missouri. It was the grimmest 90 minutes since Wimbledon last met Luton Town.

In their desire to render the state's punishment humanely impersonal - a curious paradox which provided the programme's central fulcrum - Missouri switched from the gas chamber to that most chilling of modern phrases, the lethal injection. You might have thought that an injection would be administered by an individual - a doctor, probably - but in order to make the process as impersonal as possible, a contraption was invented specifically for this purpose. We saw this death machine from every possible angle, watched the pistons of its automatic syringes pumping away efficiently in the three-stage process devised by its inventor, Fred Leuchter, and wondered what kind of dreams Mr Leuchter, a full-time Capital Punishment Systems Designer, dreamt.

Robert Lockhart's creepy score brooded ominously as we saw Leuchter descend into the cellar of his home to show us the prototype killing machine: it was like entering Buffalo Bill's lair in Silence of the Lambs, and appropriately, for Leuchter's pieces to camera, director Stephen Trombley lit the inventor harshly from above, in the tendentious manner favoured by horror movies.

Just as chilling were the scenes in which a committee of penal functionaries from the Corrections Department met to iron out minutiae in the Protocol, the procedural rules whereby the lethal injection is administered. The Protocol, like the injection itself, is designed to dehumanise the process, to spread responsibility and relieve stress on the administration. In a situation which echoes the one blank round in the firing squad, for instance, neither of the two operatives who actually start the machine knows which of their simultaneously-pressed buttons has activated it.

At no point in the entire process, from the moment the condemned man is informed, a week beforehand, of his execution date, to the final test for life, is there any room for personal initiative: the Protocol operates like some complex, Byzantine religious ritual, taking the whole grisly procedure out of the human into some other, more ordered realm.

The elaborate process didn't fool the death-row inmates at Potosi Correctional Centre, though. 'You cannot commit a clean murder,' one said, spearing the Protocol's rationale neatly. When Tiny Mercer, the first inmate to die by lethal injection, was executed, the authorities showed sex films on the prison's TV system, to take the other inmates' minds off what was happening. It seemed an appropriately impersonal way of hiding an impersonal process.

In the last part of Gallowglass (BBC 1, Sunday), Nina finally died, but almost as an afterthought, and not before Sandor - who could not have been more obviously deranged had he the word 'Psycho' tattooed in green ink across his forehead - had had the good grace to impart a certain symmetry to the plot by flinging himself in front of a train at Manningtree station. Though he managed to get his hands on her at long last, he was ultimately destroyed by Nina's revelation that their love affair had been purely expedient. 'You never removed the chain,' she explained, which you might have imagined an intelligent chap like Sandor would have twigged could make a difference to a relationship.

Before Sandor became just another incident on the line at Manningtree, though, he managed to pass on the seeds of his psychosis to the simpleton Joe, last seen using Sandor's cut-throat razor and explaining how he had, in effect, become his mentor. Perhaps it was he who killed Nina; perhaps it was the handsome Italian chauffeur who, one presumes, replaced Paul; it was difficult to feel concerned. This was another of those modern British crime stories, so reflective of the national spirit, in which all the characters are complicit and / or repugnant to greater or lesser degree. As such, the only disappointment was in the paucity of characters who wound up dead. Couldn't Joe have killed his step-sister, or something? Himself, perhaps?

In a desperate attempt to stave off the kind of long, lingering slow death it experienced in its debut, Saturday Zoo (C4, Saturday) plunged downmarket with a determined push for the more tabloid end of its potential audience which had even the show's main guest Jimmy Nail chastising Jonathan Ross for his cheap cracks at the expense of the show's all-women band. After last week's cheerless showing, the sketches were kept to a minimum - sensibly so if the slack Godfather / Royal family spoof was anything to go by. Instead, the show's hottest acts were wheeled on early: the charismatic comic Denis Leary, who gives the impression of a comet fast approaching burnout, offered a sneering speed-rap torrent of derision for ex-President Bush; and the show's swishy Queen Bitch Hollywood gossip duo, Bruce & Larry, contributed all-too-believable celebrity apocrypha. 'That Mickey Rourke, he has a terrible temper - one day I was shopping at Bloomingdales, and he struck me full in the face with a baguette]' 'You're kidding]' 'Kidding? No, it's a private fantasy of mine . . .'

For a live show, though, precious few chances were taken. The slot in which Ross was hypnotised by a 'regressive hypnotist' and recalled earlier lives as Neville Chamberlain and Jesus Christ was almost funny, but the only scent of danger came in the sketch in which professional loose cannon Rowland Rivron played a male supermodel, Pork Scratchings. You could tell by the nervous gleam in Ross's eyes as Rivron thrust his supposedly collagen-boosted buttocks in his face that this one could go either way - as, indeed, could Pork himself. Ooops] That Saturday Zoo sense of humour must be catching.