Last Night's TV - Coronation Street, ITV1; The World's Fattest Families and Me, Channel 4

Back on the sunny side of the street

If I lived in Weatherfield, I would never get out of bed on a bank holiday. Christmas Day is deadliest: there have been more heart attacks, car crashes, suicides, murders, drownings and electrocutions over the Christmas period than most of us have had turkey dinners. But on May Bank Holiday, too, it is well worth cowering under the duvet in case the Grim Reaper calls – not that these tactics did poor Blanche any good. In last night's Coronation Street, she snuffed it in her sleep, somewhere in Portugal.

In truth, this was not unexpected, since the actress who played her, Maggie Jones, died some time ago. But it was jolly unexpected for Blanche's daughter, Deirdre (Anne Kirkbride), who promptly filled up like a reservoir high on the moors in winter. Nobody sobs quite like Deirdre, and heaven knows she's had plenty to sob about down the years. Being married to Ken, twice, is not even the half of it.

Mercifully, I made it to the volume control just before Deirdre started crying, which is a noise like a combine harvester starting up. The circumstances of Blanche's death then unfolded. She had gone to Portugal with her friend May, but blow me down if May hadn't come home weeks ago, and last night she dropped round to speculate that Blanche had stayed on in the sunshine with an "interior motive", having met a chap called Arnold. For those of us with long Weatherfield memories, this rang alarm bells. Emily Bishop was the last Coronation Street biddy to be swept off her feet by a chap called Arnold, about 30 years ago, and he turned out to be a bigamist. Surely this Arnold couldn't be that Arnold?

More to the point, how could anyone fancy Blanche? "It's not like she was sweetness and light 24/7" sniffed Deirdre, which would have brought the house down had anyone been in the mood for laughter. Evelyn Waugh once observed, on hearing that doctors had removed a benign tumour from Randolph Churchill, that it was a typical triumph of modern science to take out the only part of Randolph that wasn't malignant. In that respect, if in no other, the late Blanche Hunt merited comparison with Randoph Churchill. May, however, reported that Portugal had brought out Blanche's benign side. "With the sun on her specs and the breeze in her slacks, she was a different person."

With the sun on her specs and the breeze in her slacks ... has any soap ever been as gloriously written as Coronation Street? Last night's laurels go to Jonathan Harvey, who was a playwright of considerable renown before taking the Granada shilling. He once admitted that he resisted their overtures at first, thinking that Coronation Street was beneath him, but in fact, it's precisely the other way round; he's proved that he's up to it. Besides, who wouldn't want to join a list that already features Jack Rosenthal, Jimmy McGovern, Frank Cottrell Boyce, Russell T Davies and Kay Mellor?

Anyway, Harvey last night had to wrestle with a classic Corrie counterpoint. When tragedy is brewing in one corner of the street, you can be sure there's pure comedy being distilled somewhere else – here it was in the travails of Norris Cole (Malcolm Hebden), being kept prisoner at a cottage in Brontë country by loopy Mary (Patti Clare). Mary is a competition nut, and had set herself the ultimate challenge of winning Norris's hand in marriage. But by the time she had cut off the phone lines, trod on his glasses and tried to tend his sprained ankle by massaging his inner thigh, Norris knew that he was starring in a re-run of Misery, with him as James Caan to her Kathy Bates. "Would you rather be buried alive or bleed to death, Norris?" she called, as he limped down the stairs. He stopped, stock still. "No more than 30 words," she added. "First prize a week in Dracula country."

I love Coronation Street's occasional excursions into high farce. When EastEnders tries it you'd do anything not to watch, from cleaning the lavatory to disembowelling yourself with a rusty coathanger. But Corrie's parallel reality has always been inclined to deviate from the straight and narrow, and never more so than in a general election week. Nobody's talking Brown, Cameron and Clegg in the Rovers, and even though it's several weeks since these episodes were recorded, this seems like a missed opportunity. Maggie Clegg was Betty Turpin's sister, who adopted Betty's illegitimate son Gordon, which surely makes the Liberal Democrat leader a distant relative.

Another slight implausibility about Corrie struck me last night. Where are the really fat people? You would bet your last cheesy Wotsit on there being some serious blubber in a real back street like that, yet you have to go to Kevin Webster's garage to find the really big spare tyres. The reason this occurred was that I also sat through The World's Fattest Families and Me, in which Mark Dolan, the poor man's Louis Theroux, travelled from Tonga (how nice to find a topic that demands a trip to the South Pacific) to Mexico to the United States, in search of the morbidly obese. He found them, too, not least in Los Angeles in the 46-stone form of 32-year-old Michael, who underwent radical gastric surgery to help him lose weight. "I want to do something I've not done in the last nine years," said Michael as he prepared to go under the knife, "and that's dance." Sweet.