My Friend Gerry used to say that he'd stop a speeding bullet for Grace Kelly. Every time Rear Window was shown on the telly, Gerry used to shout at James Stewart, incredulous that the man should spend so much time scrutinising his neighbours, when such adorable fruit as Grace was there, available for the, er, plucking.

Until recently my chosen screen amour was Lauren Bacall (as in To Have and Have Not), borrowed years ago from a lesbian friend of mine, who first drew my attention to those lips and that voice. So Lauren it was - until I clapped eyes on Caroline Catz, the black-haired, ruby-mouthed Dawn from The Preston Front (BBC1, Mon). Since discovering her, however, it has been hard for me to concentrate on this series as a bit of telly. But discipline is a vital part of the critic's armoury, and I steeled myself this week - and did the deed.

And was rewarded. True, the plots are a bit contrived, involving the usual far-fetched comedy stuff of impersonation and misunderstanding. But this is okay-ish, for they really act as a vehicle for the series' great strength - which is its excellent, observational comic writing. In this episode, for instance, the outstanding funny scene was Spock the Schoolmaster's one-sided dialogue with a sullen fourth-form no-hoper (who only likes drugs and eating); and his subsequent appeal to the restaurant owner, Mr Wang, to assist "the youth of today". "But I don't like the youth of today," replies Wang, "I hate them." It was a nice subversion of the usual platitudes concerning youth and opportunity.

The switch from acerbic comedy to pathos is well handled too. The great dramatic scene last week involved Eric's determination to sacrifice himself for Dawn - by convincing her that he no longer loves her, so that she will spread her wings and achieve what he cannot. It was very moving and unexpected. Even if I did find myself yelling at Eric, "If you don't want her, you fool, give her to me!"

Little pathos, but lots of good fun is also to be had in Cadfael (ITV, Tues), the adaptation of Ellis Peters' tales of a monk sleuth in the days of good ol' Empress Maud. The moment it starts, the phrase "loving attention to detail" comes to mind. GCSE classes in mediaeval history are probably shown videos of Cadfael, and asked to note the looms, lasts, wattle and daub of life in the Middle Ages. And the truly appalling haircuts. "What would you like this week, sir?" says Wart the barber. "Oh, the usual rat's tails, with a lump of grease on top, please."

My quibble - a heretical one - concerns Cadfael himself, as depicted by Sir Derek Jacobi. In the books Cadfael was a grizzled Welsh veteran of the Crusades, come at last to God after a sinful life. Jacobi's Cadfael is - by contrast, a retired theatre director from ye Home Countyes - exhausted from his latest cycle of Mystery Plays - who thinks it would be nice to spend a year or two in retreat. A flaw, but not, I think, a fatal one.

And now for a whodunnit worthy of the monk himself. Who threw the baby bird into the river full of piranhas? And don't give us any of that, "we just came along with cameras rolling, when the chick slipped off the branch, squire" nonsense. The first Attenborough line in Wildlife on One: Piranhas (BBC1, Tues) was this: "Red-bellied piranhas, and they are hungry. Above them a young white egret." And then, whoops! Oh dear, a nasty flurry of fins and feathers as egret and piranhas met - in the water. Well, you can't fool me. This was no accident; someone in the film crew helped nature take its usual unpleasant course, by giving the egret's tree a jolly good shake.

Still, murder was preferable to the two other fashionable ways of packaging natural history these days: anthropomorphism ("this is the tale of Pete the piranha and Eric the egret"), or - much worse - celebrity endorsements for favoured species. Last week on ITV, for instance, Debra Winger was with the panda, leaving me to wonder which famous person might usefully encounter the piranha. I finally settled for Cilla Black.

Who, being a young pop star, probably moved into her first flat in the period covered by All Mod Cons: The Pad (BBC2, Mon). This is a lovely series, demonstrating once again the cardinal virtues of good factual TV: excellent archive, good soundtrack, witty editing, spare and understated scripting, and vivid, animated sync. A couple of examples should be sufficient. At the start of the show the narrator told us how, in the Sixties, young people escaped from the parental home (which one contributor described as a kind of fashion prison), and into their own "pads". This was accompanied by the lyrics of "We gotta get out of this place". But to pass ironic comment on how rebellion turned to consumerism "Wild Thing" played over a section on the desirability of new, one-cast polyurethane chairs.

According to a chap called Colin Eyre, early Habitat was a "cornucopia of wowness!"; Larry Viner told of how, when budget lagged behind desire, "I had the waterbed, but I couldn't afford the heater." Viner also recalled how he changed his posters - from Marx to Dylan - with prevailing fashion. "I have to confess," he told us, "that I was extremely affectatious".

And if you wonder what that means, ask Mark Lamarr, presenter of the live Festival show Edinburgh Nights (BBC2, Mon). It's not that Mark himself is affectatious; he isn't. But Lordy, Lordy, the people he got to talk to! The least peculiar was an American man in a kilt, with a voice like that used by Richard Dreyfus in The Goodbye Girl when asked to play a camp Richard III. After that it was downhill to Lalaland. At times the sensible Lamarr was like an astro-physicist marooned in an alien abductees convention.

Readers of last week's review may remember my suggestion - a propos Channel 4's renegade TV - for a "Nail your Dick to a Plank" season, celebrating sadomasochism. This was, of course, a joke. Or was it? The principal item on Edinburgh Nights featured clips of - and a discussion about - a man who did actually go in for nailing his cojones to the mast, to wit: "Artist, masochist and longest survivor of cystic fibrosis, Bob Flanagan."

Actually the dick-nailing was not itself shown on BBC2, though a neat bit of cock and nipple clamping - as well as Flanagan's eventual death - was. At which point someone called Patrick McGrath delivered himself of the view that "this candour can be quite disturbing to a British sensibility." As opposed, presumably, to the Finns or Paraguayans of McGrath's acquaintance, who like nothing better in the long evenings than to watch a man having his genitals pulped on screen and then expiring noisily. What planet does this guy inhabit? Planet Late-night Art Talk, where the peculiar Ulsterman and film critic Mark Cousins can say - in his weird voice that lifts at the end of each sentence - that, "I started to swoon. But I thought, this is great. Everything should be showable in film." Sure, Mark, but should everything be shown? That, you see, is a completely different question.

And one that may be bothering the person who commissioned Game of War (Channel 4, Sun). This is a televised war game complete with a big table and plastic bits and generals. The latter re-fight old battles, with a couple of capricious umpires deciding who they think ought to win. It is not at all the lively TV that, for instance, Phil Grabsky's Great Commanders was.

So to liven it up a bit it is presented by Angela Rippon, a splash of female colour in this grey, solipsistic assembly of men playing games. Angela is there to act as an intermediary between the anoraks and the viewers, so - every now and again - she asks one of the boys, in tones of gushing enthusiasm, "Oooh! What's going to happen next?"

But this is a doomed enterprise because, as Jackie Mason might have put it, "Women don't like playing with soldiers. They don't, and that's it." Angela is like a well-meaning and affable maiden aunt asked to babysit her teenage nephews, and - walking in on a rave - determined to enjoy herself. "I see, that's E is it?" says Auntie Angela, "it looks like tremendous fun. No, you go and have sex in the corner, Ethan. Now, if I were a bit younger ... "