Last Night's TV: Waterloo Road/BBC1<br />The Eiger: the Wall of Death/BBC4

Waterloo Road – now into its sixth series – is kept fresh by periodic decapitation. One head goes and another arrives, to be stitched into place on the bleeding stump. The operation doesn't always take, though it's probably too early to say whether Amanda Burton, the latest replacement, will ultimately be rejected by the host body. She's certainly a matching donor in terms of her character, this particular headship calling for a melodramatic back-story (one recent headmistress had spent time working as a prostitute) and a positively magnetic ability to attract trouble. Mrs Fisher meets the first requirement since she's just taken a year and a half off to cope with the psychological trauma of having her oldest daughter go missing and things look very promising on the second count too. As one of her staff members put it – a little way into the chain of catastrophes that fills the timetable at Waterloo Road – "Parental punch-up, mass evacuation, asthmatic pupil... talk about a baptism of fire."

She didn't know the half of it, because her deputy head was having a signally bad day, too, having accidentally slept with the headmistress's daughter the night before. Being a conscientious type, he was understandably less than thrilled when the one-night stand he left in his bed that morning pitched up at school assembly in a uniform as part of the new term's intake. Meanwhile, Mrs Fisher was dealing with a troublesome new pupil – a home-schooled brat who was determined to get herself expelled before the week was out – and started her campaign by taunting the disenchanted English teacher with her precocious grasp of the syllabus: "Why are we doing The Waste Land?" she moaned, "I find it so simplistic." Sexual dynamics in the staffroom have also been given a little paprika piccante with the arrival of Ms Montoya, a Spanish teacher who had come to work dressed as if it was Friday night and she was on the pull.

Waterloo Road has absolutely nothing to do with what it's actually like to teach in a school. It's just a handy container for a set of storylines, which are presented to us in an embarrassingly frictionless way. Wild uncontained arguments are suddenly resolved with 30 seconds of impassioned speech and – a common fault in the soapier kind of television drama, this – virtually nobody behaves as if they are in a public space and subject to the judging inspection of everyone around them. So Mrs Fisher had a hissing row with her wayward daughter in the middle of the assembly she'd just addressed on the issue of discipline, and Mr Mead, the deputy head, furtively asked for a quiet word with Jess – his one-night stand – in a way that could only suggest to her school friends that she was about to have his baby. Last night's episode ended – somewhat implausibly – with the entire staff-room turning out to search the moors for a missing girl, the alarm having been sounded when this conspicuously chippy and capable child had been missing for only one and a half hours. And, yes, I can see that Mrs Fisher might be a little over-sensitive to disappearances but would the local police have the time to over-react quite so wildly?

There was Alpine drama in The Eiger: the Wall of Death, a documentary about the fabled North Face that commented on its seductive power for journalists by succumbing to it itself. I'm pretty sure that this documentary – in fresh reiterations – comes around about once a decade, but if you have a weakness for the self-mythologising that mountaineers are fond of (I do) it's always worth watching. They had some fine footage from the Stollenloch Window, which gives access to the North Face from about half way up. "Why don't they just start from there?" asked my wife. I don't think she's one of nature's mountaineers.