The BBC's Reeta Chakrabarti: Senior Tories deny revelations will throw a shadow over conference

In the first extract of his memoirs, serialised in the Sunday Times, Mr Major criticises her for possessing "warrior characteristics" that were "profoundly un-Conservative".

Lady Thatcher is dismissive of the memoirs. Her spokesman said: "She has not looked at that."

Mr Major says she was inconsistent over Europe, contradicting her positive public stance with hostile private attacks.

BBC News' Guto Harri: Row threatens to overshadow conference

He also claims Lady Thatcher's private view on Europe can be summed up as: "Never trust the Germans."

He says: "Two world wars, she thought, proved the country was expansionist by instinct. Britain's role was to stop it."

'Another Margaret'

But in practice, her approach in government was "as much pragmatist over Europe as she was sceptic".

Mr Major said: "Overall, the prime minister was undeniably 'on board' the European train, even though she was uneasy about where it was heading and complained loudly at every stop.

Lady Thatcher had "warrior characteristics", Mr Major said

"The trouble was there was another Margaret, usually confined to private quarters, whose gut reaction was much more hostile to Europe.

"Like a shorting circuit she flickered and crackled."

Although he supported Lady Thatcher throughout her time in power, Mr Major said that he was in private becoming "uneasy" at her increasingly "autocratic" approach.

"In public, her certainties were off-putting. In private she was capable of changing her mind at bewildering speed until she had worked up her public position," he said.

Mr Major's disclosures, on the eve of the Conservative Party conference, follow revelations in the published diaries of his former private secretary, the late Judith Chaplin, that he had wanted Lady Thatcher "destroyed".

It also follows Mr Major's public dispute with former chancellor Lord Lamont over the events of Black Wednesday in 1992.

Mr Major will not be in Blackpool next week, although Lady Thatcher is due to attend.

Senior Tories deny that Mr Major's memoirs have the potential to re-open old wounds and disrupt the conference.

"No rift" between Thatcher and Hague, says her spokesman

Shadow Defence Secretary Iain Duncan Smith told GMTV's The Sunday Programme it was "in the past".

He also dismissed Sunday Times reports that Lady Thatcher has privately mocked current Tory leader, William Hague, as "wee Willie" who had gone soft on Europe.

Lady Thatcher's spokesman denied that there was a rift between her and Mr Hague.

And Mr Hague predicted Lady Thatcher would deliver a completely different message during the forthcoming conference.

Meanwhile, Mr Major is quoted as saying that former leaders "ought to support William and not get in his way".

Asked whether the same people were on Mr Hague's back as were on his, Mr Major replied: "A lot of people might say that. I couldn't possibly comment."

Secret sister

As more details of Mr Major's time in office emerge, he is also set to reveal details of his personal life when his memoirs are published.

The Sunday Times reports that he has discovered he had a secret half-sister, Kathleen Lemon, who is now 75.

She shares a father - the travelling showman Tom Major-Ball - with the former prime minister, his older brother Terry and his sister Pat.

Mrs Lemon is reported to have been the result of an adulterous affair in the 1920s between Mr Major-Ball and a young dancer.

In May, Mr Major was reported to have met a half-brother he had not known existed in the US.