Last Night's TV: Waterloo Road/BBC1<br />Midsomer Murders/ITV1<br />The Secret Life of Waves/BBC4

Don't you just love the National Television Awards – the way they puncture the rarefied illusion that the whole world is loving Mad Men or Skins or Peep Show, and where Ant and Dec and David Jason win a prize every year, even if they spent the previous 12 months sunning themselves in the Bahamas (hats off to Sir David for managing to remain in the O2 throughout Stephen Fry's embarrassingly luvvied-up introduction)? It's the sort of popularity contest in which Waterloo Road wins the Best Drama category against Sherlock and Shameless – the biggest shock of the night, although try telling that to Helen Worth, Gail from Coronation Street, who looked like she'd just had a tram come though her living room wall after EastEnders nicked the Best Soap award.

Anyway, this is a roundabout way of saying it was time I revisited Waterloo Road. I should long ago have been excluded for non-attendance of this saga of a Rochdale comprehensive, usually only turning up for the first day of every term, before bunking off for the duration, a bit like new boy Kyle, the sort of student who arrives at school with his mother and rottweiler in tow (the mother was more menacing). Kyle was played by George Sampson, who won Britain's Got Talent in 2008 for his street-dancing act, and he wasn't the only new but familiar face around here since I last attended this bracing establishment.

The bloke from Men Behaving Badly seems to have been transferred – not for behaving badly, I hope – and his place has been taken by that forensics woman from Silent Witness, not Emilia Fox but the one before her, whose teenage daughter is played by teenage mum Sarah-Louise Platt from Coronation Street (the 27-year-old Tina O'Brien in a school uniform; it doesn't look too St Trinian's), and who seems to have spent the previous two years as a runaway. Anyway, she falsely accused the Britain's Got Talent winner of touching her leg in detention (or "the cooler" as it's known in these parts) and, understandably aggrieved, he set his rottweiler on her. It all ended in a hilarious scene, reminiscent of the Monty Python sketch where Michael Palin is mauled by a stuffed lion, as the dog leaps on the Spanish teacher. Great fun, as Miranda's mother says in Miranda, and I'll see you all next term.

I'm surprised Midsomer Murders has never won a National Television Award, after all it's everything they seem to be about – cosy, undemanding, middle-of-the-road, Michael McIntyre-for-best-comedy-act sort of thing. It's a pair of Marks & Spencer cotton slacks of a drama, and the French love it, just like they love Marks & Spencer cotton slacks. They think this is how we live, driving between gorgeous Cotswolds villages in Range Rovers before taking tea on the lawn and politely murdering each other. Anyway, the important thing about last night's mystery was that it was John Nettles's last case.

Nettles is a deeply reassuring figure, with his warm craggy smile and sensible attitude to human foibles, and with a short break in between, he's been playing the same character since 1981, first as Jim Bergerac in Bergerac and then as Tom Barnaby in Midsomer Murders. In his late sixties in real life, Nettles-as-Barnaby is well past the police retirement age, and last night's swansong found him taking a short break at a country-house health (ha-ha) spa with his schoolmarm'ish wife Joyce (Jane Wymark) in preparation for a forthcoming medical.

Having turned down the offer of her hot stones, Barnaby reluctantly agreed to the new-age masseuse's offer to read his aura – she discerning distress about his coming birthday, since it emerged that his father had died on this same anniversary. In between these intimations of mortality – Barnaby wandering around like his fruit juice had been spiked – was an enjoyably silly whodunit in which victims were dispatched in the flotation chamber, by way of a sabotaged weights machine, and so forth. The big question, however, is whether the format will survive the passing of its greatest asset. Inspector Morse managed it with the inspired casting of Laurence Fox in Lewis, but in casting Neil Dudgeon as Barnaby's replacement, ITV seems to have taken the safe continuity option over vigorous reinvention. But then what do expect of M&S slacks?

I don't suppose The Secret Life of Waves will be winning any National Television Awards next January – that David Malone will be hopping on stage at the O2 to be glad-handed by Dermot O'Leary, although I hope that Bafta take note. Very unassuming it was, but utterly brilliant. David Malone was enthusiastic without being ENTHUSIASTIC, and was so obviously engaged in his subject that you felt you were learning alongside him. And what an unexpectedly fascinating subject.

Waves – we think we all know waves, bouncy wet things that fascinate surfers but make most us seasick. The relatively new science of waves – instigated by the needs of Second World War military planners – has shown that waves are not really made of water, that they are in fact bands of energy using the surface of the water as a medium, and that the sound we hear when they crash on the beach is in fact the popping of trillions of little bubbles. And there are waves beneath waves, often travelling in the opposite direction. It's being shown again on Saturday (8pm BBC4). I promise you won't look at the surf in the same way again.

g.gilbert@independent.co.uk