Review: Judi Dench and Eileen Atkins head a superb cast in Elizabeth Gaskell's classic portrait of a town on the brink of change

Cranford, BBC1; This is Civilisation, Channel 4

A classy week on TV, this one. Shall we start with the period drama? Anyone with a frilly-hat intolerance, please rejoin us at paragraph five. For by their bonnets shall you know the ladies of Cranford. Dame Judi has a sweet, dappy straw one; Dame Eileen Atkins's is grey, because she is clever; Imelda Staunton, meanwhile, sports a mob cap and two big frilly bows. How very dare she!

To call Cranford a comedy of manners is to make too great a claim for it; it's more of a comedy of minutiae. Trivialities are deeply important, haberdashery a matter of life and death. A sample line, crowed by Julia McKenzie (bonnetless, indeed, but wearing a Midlands variant on a mantilla): "What is all this agitation? Are the summer gloves come in?" One of the most dramatically vivid scenes was a cat swallowing a piece of lace.

Played straight, all this would be unbearable, but this BBC production by Sue Birtwistle has great comic flair. Each scene is suffused with exactly the right ironic wattage; neither so dim that we cannot see what the joke is, nor so bright that it shrivels the characters into caricatures. The scene in which Dames Eileen and Judi, playing unmarried sisters ever concerned with propriety, retire to their separate rooms to suck oranges, was deliciously done; Judi Dench, as Miss Matty, said "little babies" as if it were a heart-stoppingly scandalous phrase. You could imagine Mrs Gaskell's shoulders rocking with laughter.

The series has taken five years to make; upheavals have included a change of director. It's been worth it. Comic tone in a TV adaptation is as fugitive and fragile as cherry blossom in a high wind. It can disappear without anyone noticing. Someone mislaid Posy Simmonds's wit during the title sequence: a perfect choice for the job, she was woefully underused - there is only so much gentle irony that an illustrator can invest in a village landscape. The straight scenes tend to feel cloying, but Simon Woods's beautifully earnest doctor gets us through. Generally it's a triumph of gentleness, a gentle kind of triumph. People who like this sort of thing will like it very much.

"I'm a stick in the mud," said Kenneth Clark at the end of Civilisation. "I prefer gentleness to violence. I believe in courtesy. I believe human sympathy is infinitely preferable to ideology..." His very real fear of Marxist socialism and its threat to overwhelm the world crept in at all the cracks in Civilisation. Nothing dates quicker than a fear that has now been proved unfounded. It ages the programme more than anything else about it, even the wonderfully slow, wobbly zooms. The idea of updating Civilisation is absolutely justified. I just wish a woman had been hubristic enough to do it. Instead we have Matthew Collings's This Is Civilisation. (The title conjoins Clark and Collings's own former series This Is Modern Art in one breathless impertinence.)

He is not a charming on-screen presence, striding round the temples of Philae and other cultural hotspots with his arms swinging awkwardly, as if he had specially weighted hands. But Clark was not instantly sympathetic either. Both of them win you over with their content, the pure ozone of their simply expressed ideas. It is rare, intoxicating even, to see an essay on TV where the footage suits the concepts, rather than the other way round, and where the talking head is the author of the piece, rather than a puppet. I haven't seen anything this good since Jonathan Meades.

Collings lacks Meades's witty, self-mocking impulse, which means he can be vast and monumental. What he lacks in modesty he makes up for in ambition. He gallops across Western art, from Greek kouroi to Alison Lapper Pregnant, comparing and contrasting constructively. His forays into colloquialism can be awkward - "lookatability" isn't an elegant critical term,is it? - but sometimes charming. "Let's grasp how truly odd it was for Greeks to celebrate the human in a minute, after the barbaric ad break."

What is best about him as a critic of religious art, however, and what makes him feel brilliantly contemporary, is his godlessness. He contemplates images of the crucifixion clear-sightedly, unblinded by veneration, contrasting Christ's "abject, humiliated body" with the perfect musculature of the Greeks and reminding us that Christianity is "a death cult". He draws a line between Islamic patterns and Jackson Pollock: undecipherable, abstract - "the specialling-up of space". Collings's clumsy demotic grows on you.

Notable shows last week also included Exodus, a Channel 4 adaptation of the Old Testament that was mesmerisingly florid but impossible to take seriously; and The Blair Years on BBC1 (left), commendably devoted to policy rather than personality. It outshone Andrew Rawnsley's recent attempt in most regards except the irritating soundtrack - flamenco guitar and castanets. Why?