Shirley Porter: Rich, flashy and corrupt with it. She's nothing like a Dame

The lady owes £27m for her part in Britain's most notorious vote-rigging scandal. With a £70m personal fortune, she can afford to pay it. But you've got to catch her first

British public life produces relatively few political exiles. Victims certainly, such as Peter Mandelson or Michael Portillo; and villains, too, like Jonathan Aitken and Jeffrey Archer; but no one who has been forced to leave the country because of their record in government. And local government at that.

But Dame Shirley Porter, former leader of Westminster council, looks like becoming our first politician to move abroad permanently in the wake of her misdemeanours. For last week's unanimous ruling by the House of Lords marks the end of Dame Shirley's battle to clear her name over her authority's notorious homes- for-votes policy in the 1980s.

It is worth recalling just what this entailed. Her "homes for votes" strategy was simple: a four-year plan to ensure the 1990 local elections were won by the Conservatives. Council homes in eight key marginal wards would be put up for sale, under the "right to buy" policy, thus attracting more voters inclined to vote Conservative; the poor and the homeless (more likely to vote Labour) would be placed in "appropriate wards". In practice this meant decanting some of them into two tower blocks contaminated with asbestos. The BBC's Panorama programme investigated the scandal in 1989 and this was followed up by a damning report by the district auditor and a decade of legal battles.

Now Dame Shirley must also hand over £27m as a surcharge – effectively a fine – for her part in the affair. Remarkably, she could afford to pay a debt of that magnitude, and still have some change, thanks to her personal fortune, estimated at £70m. But she won't be parting with her cash any time soon because she and her funds have taken up residence in Haifa, Israel.

What she has lost, however, is any remaining shred of credibility. The language used by the Law Lords sees to that. Her policies represented "a deliberate, blatant and dishonest misuse of public power" and "wilful misconduct". She and other Tory councillors were guilty of "disgraceful gerrymandering". Worst was thecondemnation of her and her former deputy, David Weeks, as corrupt. In the words of Lord Scott: "The corruption was not money corruption. No one took a bribe. No one sought or received money for political favours. But there are other forms of corruption, often less easily detectable and therefore more insidious. Gerrymandering, the manipulation of constituency boundaries for party political advantage, is a clear form of political corruption."

It is a bleak denouement for the "iron lady of the town halls", a Thatcherite star when she took over Westminster in 1983, who pioneered the privatisation of local services and set a poll tax of £36. Until the homes-for-votes scandal broke, her most notorious act was to sell off Westminster's public cemeteries for 15p to a Panamanian-registered company. They were later sold for £1.2m. It was the sort of audacious move that enraged the left and pleased her mentor Margaret Thatcher in equal measure. Indeed Dame Shirley had a good deal in common with Mrs Thatcher. They were about the same age, they both enjoyed a scrap and both were grocers' daughters. Dame Shirley's father, Sir Jack Cohen, was the more successful, having built up the Tesco empire, while Alderman Roberts never progressed beyond his corner shop and sub post office in Grantham, but they both inherited a good deal of drive and homespun philosophy from their fathers.

Shirley was born in Clapton, east London, Cohen's youngest daughter. Legend has it that Jack started out selling matzos from a barrow. By the 1930s he had three or four shops, having co-operated with a merchant called TE Stockwell whose loose teas he packeted. The chain was known as Tesco and his daughter played her part: "Our kitchen was my father's market research department. There was no such thing as focus groups then."

Famously, Cohen's early business slogan was "pile it high and sell it cheap", but that was replaced by "YCDBSOYA" – "You can't do business sitting on your arse." Shirley said she took it to mean that, "no matter how clever or personable someone is, at the end of the day those who work the hardest normally win". She went to the Warren School in Worthing (where she says she was bullied for being Jewish), and then finishing school in Lausanne. At 18 she married Leslie Porter, a returning soldier, who became president of Tesco, retiring in 1991. She lived the life of a typical wealthy wife and has a taste for loud clothes, "more Harrods than Harvey Nichols", says an acquaintance. On a cruise in the Caribbean earlier this year, fellow guests were entertained by a constantly shifting array of cruisewear. She would change as often as five times a day and was always perfectly manicured, maquillaged and bejewelled.

By the mid-1970s her energies had begun to find new outlets. While Leslie Porter was running the company, she too made her presence felt. Fellow board member and eventual successor as head of Tesco, Ian (now Lord) MacLaurin called her "divisive, pushy, egotistical".

Dame Shirley found it easier to impose her will on Westminster council than on the former family firm. By the time she was 40 she was a mother-in-law and justice of the peace, in which role she found herself dissatisfied with the way the legal system was run. (Not as dissatisfied as she is now, one imagines.) The family moved to Hyde Park and she became a councillor for the Hyde Park ward, a safe Conservative seat. "I was not in politics, I wanted to improve London," she said.

It was rubbish that set her pulse racing. Even her opponents conceded that she enjoyed some success in cleaning up central London. She was good at getting some things done. Maybe, in some parallel universe where Shirley Porter managed to keep out of trouble, she could have gone on to be a minister in the Thatcher-Major governments. The great Conservative collapse did for part of that dream, but her own flaws were well to the fore. For, despite the similarities, Dame Shirley was neither as clever nor as skilful a politician as Thatcher. Her paranoia about the left, however, rivalled Thatcher's in intensity.

When she hatched the vote-rigging plot, one of the documents circulated to her inner circle said: "Imagine socialists running Buckingham Palace, militants lording it over Parliament and controlling Downing Street, left-wing extremists interfering in the daily running of business." She would do anything to prevent such a calamity. In fact, Labour probably would never have won Westminster in any case, but that did not stop Porter from engineering one of the worst examples of political corruption in modern times. Like Aitken, Archer and Neil Hamilton, she is never that far from the headlines even today, and is a living reminder of the excesses of the 1980s.

It has taken many years for the district auditor's charges to stick. According to Dame Shirley, her self-imposed exile is because: "We were hit by a succession of family tragedies. After my grandson was killed in a car crash, I wanted to be with my daughter, to spend more time with her and our other grandchild. My husband was unwell. Our London home had been damaged by fire. We already had many interests in Israel. It seemed the right thing to do at the time." It still does.