The Weekend's Television: Cranford, Sun, BBC1The Fattest Man in Britain, Sun, ITV1

Lots under the bonnet

Cranford isn't really a drama any more, it's a gift bouquet. Whereas the first series gave us what we didn't know we wanted, the Christmas specials have to reassure us that all the stuff we learnt to love will be tucked in there somewhere.

Hence, I take it, the very early and arbitrary appearance of Bessie the cow in her grey combinations, a garment she should surely have grown out of by now but which served as a little wink to the audience that it will be business as usual. Never mind that there didn't seem any particular rationale for having Julia McKenzie leading her down the high street with a beatific smile. A cow in grey jersey feels like an appropriate seasonal treat and needs no justification but goodwill.

There are novelties, of course. Jonathan Pryce is bolstering the series's already impressive check-list of British acting talent as Mr Buxton, a local salt-mine magnate who has brought with him his energetic young son, William, a fierce enthusiast for the railway and a promising match for poor, downtrodden Peggy Bell. William also has a misbehaving dog that dashed into the church and peed next to the altar, almost a surfeit of generosity when it comes to comedy animals. We also finally got to meet Lady Ludlow's wastrel son, Septimus, returning home too late for her death but in plenty of time to tinker with Mr Carter's will in villainous ways and allow some speculation about the exact nature of his relationship with his Italian friend Giacomo.

But the core of the thing remains the main characters, essentially distilled now to two poles. On one end, you have Judi Dench as Miss Matty, giving the thing a contact to pathos and the heartfelt, and on the other you have Imelda Staunton's wonderful Miss Pole, delivering a regular galvanising jolt of comedy. We encountered her first last night as just a scandalised quiver, the plume on her hat vibrating with shock at the fact that navvies had been seen at the George, though her face was still invisible below the edge of the frame (a nice sight gag from director Simon Curtis). And Heidi Thomas clearly loves writing for her, giving her a succession of delicious lines, from her civic triumph at the prospect that a magician was coming to town ("They will gnash their teeth at this in Missenden... they who have had the acrobats and the great bull") to her wildly improbable claims of expertise: "Surrender the carpet beater... I am no stranger to a snake," she announced when Matty's brother's belongings arrived from India and had to be checked for vermin.

There was no shortage of incident either, with plotlines so compressed that you occasionally wondered whether they'd skipped a reel. At one moment, William Buxton was looking at Peggy Bell with an appraising eye; at the next, he was proposing marriage, without any obvious intervening courtship. And the successful defeat of the proposal to extend the railway to the town was overturned with startling rapidity after Miss Matty decided to lobby for modernity and persuaded the town's ladies to take an experimental trip in a first-class carriage, an excursion Miss Pole barely perceived because she was so worried that the rushing of the passing scenery would fray her optic nerve. In fact, so neatly did it tie up its available loose ends that you wonder a little what they've kept in reserve for the second half. That it will be worth watching doesn't seem in doubt, though.

The Fattest Man in Britain looked as if it was going to be filed under Northern Grotesque. You had Bobby Ball in a cab promising his excited Japanese passengers "the eighth wonder of the world". And then you saw Georgie's pudgy hand reaching for the aftershave bottle and splashing it on underneath a bingo wing the size of a sofa cushion. When Timothy Spall, just visible inside his fat suit, began singing "Turning Japanese", complete with slitty-eye gestures, for his paying guests it looked as if we were in for an exercise of gleeful bad taste. In fact, Caroline Aherne's drama (co-written with producer Jeff Pope) turned out to be a lot sweeter and life-affirming than you might have expected, contriving a Beauty and the Beast relationship between Georgie and Amy, the community-service girl who came to clear his garden. For her, he was the dad she's never had; for him, she was the first person to care for him who didn't have an interest in him getting bigger. Although he was initially devastated by the realisation that he had a heavier rival ("If I'm not the fattest, what am I, eh? I'm just a fat man") he finally struggled out of his chair and slimmed down to win her back. I wasn't entirely convinced that it would have been as easy as it was made to look, but very happy to pretend while it lasted.