BBC2's tough yet charming documentary When Michael Portillo Became a Single Mum (15 October, 9pm), the first in a strand called My Week in the Real World, showed exactly what the Tories are missing in their current leadership crisis. Portillo was revealed as charismatic, disciplined and open-minded: likeable, in short, to the point of electability. The trouble is that although he may be prepared to play at being a single mum, on no account is he willing to slum it as the leader of the Conservative Party - even should it get past its homophobia and ask him to be its leader.
Portillo has discovered that he is far too good a television personality to revert to being a mere career politician. The indiscreet star of Andrew Neil's This Week on BBC1, he has, for television's sake, already masqueraded as a hospital porter and as a lecturer on Wagner. In this latest stunt, he was deputising for Jenny Miner, a 31-year-old single mother from Liverpool who brings up four children on the £317 per week she earns as a classroom assistant and supermarket worker. The idea, obviously, was to break every Tory prejudice in his exotic body.
"Welcome to the real world, Mikey," said Jenny with a flash of malice. But the real world was soon welcoming him back. Out in the streets of Liverpool, people were vague about his exact identity but knew he was a politician of some sort - and, therefore, a being as remote from their lives as it was possible to be. "What are you doing here?" asked a shopper at a cut-price butcher's. "Buying a chicken," he said. He chatted equally easily to Jenny's colleagues at Asda and gratefully accepted advice from his new boss, the primary school teacher.
The 12-year-old girls who came to the karaoke party hosted by Tasha, Jenny's oldest daughter, were also impressed: they thought he looked like George Clooney.
For the sake of political credibility, Portillo, not merely a pretty face, made quite sure he would not be beaten by Jenny's dire domestic economics. He did not mention it, but his first sacrifice was to deny himself any alcohol for the week, making the subliminal Tory point that alcohol is a tax volunteered by the feck-less. After a shaky start, in which the children unhelpfully tumbled pricey novelty cereals into his supermarket basket, the naturally "pretty extravagant" Portillo soon discovered bargain pizzas in the freezer department. Jenny, who every night was shown footage of how he was doing, scorned his amateurism; I thought he did rather well to end up £1.69 in clover.
Nor did he fail in his real-world jobs. Admittedly, he was not a natural in the classroom. The first day, his explanation of subtraction went well over his charges' attention spans. In a priceless moment straight out of Joyce Grenfell, he urged: "Don't worry about the ant, James." By day three, however, he was in charge. At Asda, he did not patronise Jenny and her job by pretending it was anything but drudgery - but, as one used to the frostiness of the Commons tearoom, he appreciated the camaraderie of the canteen.
The greater challenge - nothing to do with politics - lay back at home with Jenny's children. Anybody entering another person's family falls foul of its rules. Portillo was not to know that the minor Miners were allowed to leave the table without asking, or to realise that demanding that they ask to leave would cause such resentment. Bookended by bossy but willing Tasha, 12, and spirited but difficult Ellie, eight, Portillo underestimated the former and demonised the latter. "He had better not be picking on her," said Jenny on her youngest's behalf.
The boys' verdict on Portillo's parenting was that he was rubbish at it but that his cooking was worse. (I felt for his much-rejected signature dish, the banana trifle.) On her return, Jenny was just as merciless, accusing him of letting Tasha rule the roost and of intimidating Ellie. His lips bulged and his eyes liquefied. Although he admitted no ambitions, past or present, towards parenthood, he thought he had done better - slightly - with the kids than this.
It was, he said, a rough-and-tumble, physical, open-air neighbourhood: you did not know whom your children mixed with. Expectations were low. Academic success was not esteemed and there was a shortage of male role models. Jenny, with her pierced eyebrow and sly smile - every bit as attractive and competent a person as Portillo and, in some ways, with a richer life - disputed this. There were lots of dads involved with their children, even if they no longer lived with them. And anyway, about the district: "It's what you get out of it." She was the true Samuel Smiles Tory.
The programme proved only that any of us can cope with anything for a week, but Alison Cahn's beautifully cast film succeeded in its higher aim of illuminating the character of both mums, the real one and the TV fake. It also avoided sentimentality, which, given the triple whammy of Liverpool, children and a middle- aged man without issue, was remarkable. Towards the end, Michael took the children to the park and thanked Tasha for her help. "Are you going to cry?" she asked. "No, I don't think so," he said. Back home, millions shed a tear for the Tories' lost leader and for the Miners' lost father.
Andrew Billen is a staff writer on the Times