LONDON: Thirty years after Margaret Thatcher became Britain's first female prime minister, the Conservative Party is again on the brink of power and facing a dilemma -- embrace or reject her divisive legacy?

Thatcher, later nicknamed the Iron Lady, took power on May 4 1979, quoting Saint Francis of Assisi as she stood on the steps of 10 Downing Street: "Where there is discord, may we bring harmony".

But far from uniting the nation, Thatcher's radical reforms polarised opinions, leaving today's Conservatives led by David Cameron -- who pollsters tip to be prime minister within about a year -- unsure of how to define themselves in relation to her.

"I don't think there's a consensus on Thatcher, I think she's a very awkward figure for the English middle classes because people find her personally very unattractive and the things she did traumatic," said Professor Richard Vinen of King's College London, author of the recent book "Thatcher's Britain".

"There's a strong element of guilt about her. A lot of people wanted to do the things she did but not take responsibility for it themselves."

So what did her 11 years in office change about Britain? Thatcher herself was asked the question some years ago and reportedly answered, with typical fierceness, "everything".

Experts single out three main areas -- lower taxes, privatisation of state-owned firms like British Airways and British Gas, and significantly weaker trade unions, which had led a series of crippling strikes in the 1970s.

But while her uncompromising style brought about many of those changes, it is also why some Britons still see her as an uncaring figure wedded to harsh economic individualism and cannot forget one of her most famous quotes: "There is no such thing as society".

Today's Conservatives have, by contrast, worked hard to emphasise their support for liberal social policies such as gay marriage and environmentalism.

When Cameron took over as Conservative leader in 2005, his aides spoke of having to "detoxify" the party brand, while one senior Conservative warned in 2002 they were seen by the public as "the nasty party".

Asked for his views on Thatcher -- who is now 83, suffering from dementia and does not speak in public on doctors' orders -- Cameron sounds ambivalent.

"I would say I'm trying to learn the lessons of her success and apply them to today," he told a BBC documentary earlier this year.

"It was an absolutely modernising, futuristic message (that she had) and we need to do the same thing in very different circumstances."

Although Cameron seems reluctant to embrace her legacy explicitly, Prime Minister Gordon Brown has, paradoxically, been more forthcoming.

He invited Thatcher to tea at Downing Street after he took office in 2007, casting himself, like her, as a "conviction politician".

Experts say this underlines how her legacy lives on across the political spectrum.

Many of her keynote policies like lower tax and deregulation were -- until the recent world financial crisis -- warmly embraced by Brown and Tony Blair as they recast the left-wing Labour Party which Thatcher repeatedly trounced at elections into the centrist, market-friendly New Labour in the 1990s.

The credit crunch has changed a lot, though. Today's Labour and Conservative Parties are in many respects clustering behind the old dividing lines which were in place in the 1970s, on the eve of Thatcher's election.

Faced with eye-watering levels of public borrowing, Brown's government has raised the top rate of income tax and analysts say the country faces the prospect of higher taxes across the board.

Meanwhile, the Conservatives' new watchword is austerity, recalling Thatcher's squeeze on public spending in the 1980s as she sought to steady the economy.

"Both parties are reclaiming pasts they thought they had left behind long ago," columnist Philip Stephens wrote in the Financial Times newspaper last week.

It seems likely that this will also include a Conservative victory at Britain's next general election, which must be held by the middle of 2010.