'It was like Mary Queen of Scots being beheaded': Sleepless nights, political skulduggery and a coup that would change Britain for ever. Thirty years on, a gripping account of Margaret Thatcher's downfall

In June 1987, Margaret Thatcher was elected for a third term with the slogan 'Moving Forward With Maggie'. 

But just three years later, the economy was in trouble, the hated poll tax sparked riots and many Tory MPs were impatient for change. 

In early November 1990, Mrs Thatcher's longest serving cabinet minister, Geoffrey Howe, resigned dramatically, revealing the schisms that were beginning to rip the party apart. 

When Downing Street announced there would be a snap leadership election to flush out any rivals to Mrs Thatcher, she had already been warned that there were 'a hundred assassins lurking in the bushes'. 

Here, Jonathan Mayo reveals what happened as the PM's enemies sharpened their knives… 

The Downing Street staff are lined up in the entrance hall and burst into applause when Mrs Thatcher appears, wearing a burgundy suit, her hair immaculate. The former PM starts to cry  

8am, Monday, November 19, 1990

It is the day before the first ballot for the leadership of the Conservative Party. 

Michael Heseltine is Mrs Thatcher's only challenger and the Tory she sees as the greatest threat to her legacy.

At Chequers, she is in her dressing gown, going through her red boxes and getting ready to fly to Paris for an important summit with President Bush, President Gorbachev and President Mitterrand to celebrate the end of the Cold War. 

She has decided to attend to show that, despite the ballot, it is business as usual. 

Her daughter Carol asks her about today's vote. 'I might lose, but I don't think I will,' she replies.

After a five-day leadership campaign Douglas Hurd returned to No 11 Downing Street having voted 

9am

At Chancellor John Major's home in Great Stukeley near Huntingdon, his friend Jeffrey Archer arrives. 

In the past three years, Major has been rapidly promoted by the Prime Minister — first to chief secretary to the Treasury, then Foreign Secretary and then Chancellor of the Exchequer.

Archer is carrying a bundle of newspapers, some saying that Major should succeed Mrs Thatcher. 

As they discuss the future, Norma Major suddenly says: 'Do you realise we're sitting here talking about you becoming Prime Minister?' 

Her husband is recovering from an operation on his wisdom teeth and is still groggy. 

He wrote later: 'Though I was still only half-alert, the thought sank in. It was tempting to play with — but unreal, I assumed.'

In June 1987, Margaret Thatcher was elected for a third term but just three years later, the economy was in trouble and the hated poll tax sparked riots

2pm

In Parliament, Alan Clark, a loyal Thatcher supporter, is concerned about increasing support for Heseltine among his fellow MPs, so he knocks on the door of Peter Morrison, Mrs Thatcher's parliamentary private secretary in charge of her campaign, to find out what he's going to do about it.

Morrison is asleep in a leather armchair, snoring softly. Clark wakes him up and shares his concerns but Morrison is unruffled. 'Look, do you think I'd be like this if I wasn't entirely confident?'

Clark asks: 'What does the arithmetic look like?' Morrison replies: 'Tight-ish but OK.'

Clark leaves despondent. He writes in his diary: 'Peter is useless, far worse than I thought … there isn't a single person working for her that cuts any ice at all.'

10am, Tuesday November 20

In Paris, Mrs Thatcher conducts a series of meetings with world leaders. She spends an hour with Soviet leader Mikhail Gorbachev talking about Saddam Hussein's invasion of Kuwait in August.

President Bush later wrote in his diary that for the PM to be in Paris on that particular day 'seems a little odd, but maybe that gives her stature, that she's dealing with world problems'.

Midday

A refreshed John Major is watching a television in the main reception room in No 11, together with Norma and his campaign team. The result is clear: he has won 185 votes  

Peter Morrison arrives at the British Embassy in Paris with a large chart claiming to show that Mrs Thatcher has the votes she needs to win. 

The Ambassador, Ewen Fergusson, orders champagne to be on hand for the result later that day.

4pm

In the House of Commons, the first round of voting begins. The rules state that a candidate can win outright on the first ballot: 'If one candidate both receives an overall majority of the votes … and receives 15 per cent more of the votes … than any other candidate, he will be elected.' 

The rules were drawn up when it was inconceivable that a woman could become leader of the Party.

6.15pm

Mrs Thatcher is sitting at the dressing table in Peter Morrison's bedroom at the British Embassy when he hands her a piece of paper. 

He says: 'I'm afraid, Prime Minister, that these figures are rather disappointing.'

She has 204 votes, Michael Heseltine has 152 and there are 16 abstentions. The PM has 55 per cent of the vote but is two short of the total she needs to win.

Kenneth Clarke said later: 'It was the disaster we had feared … She had neither won decisively, nor lost decisively.' 

After a short silence, Mrs Thatcher stands up and says: 'Well, I know what I have to do then' and heads for the lift.

In the Embassy courtyard, BBC correspondent John Sergeant is standing at the foot of a flight of stone steps. 

Michael Heseltine is Mrs Thatcher's only challenger and the Tory she sees as the greatest threat to her legacy (pictured together) 

He has just told viewers of the Six O'Clock News that the Prime Minister will not be emerging for some time.

Suddenly, Mrs Thatcher appears and newsreader Peter Sissons, in the TV studio in London, shouts: 'The Prime Minister is behind you, John!' 

Sergeant spins round to see Mrs Thatcher heading for him, followed by her press secretary, Bernard Ingham.

Sergeant says: 'Mrs Thatcher, can I ask you to comment?' but she walks past him saying: 'No, but good evening, good evening.'

Bernard Ingham shoves the BBC man back. 

Mrs Thatcher stops to address reporters, putting a positive spin on the result: 'I am naturally very pleased that I got more than half the parliamentary party and disappointed that it's not quite enough to win on the first ballot. So I confirm that it is my intention to let my name go forward for the second ballot.'

8pm

At Versailles, President Mitterrand has laid on a dinner for the world leaders, preceded by a ballet. 

President Bush sees Mrs Thatcher walking in alone and says to his wife Barbara: 'Maybe we should go with her'.

They position themselves either side of the PM and escort her in. Mrs Thatcher reassures him: 'Don't worry, George. I'll go home and get this straight.'

Douglas Hurd said later: 'I never felt greater admiration for her than on that night.'

7am, Wednesday November 21

Mrs Thatcher has not slept all night. Her personal assistant, Cynthia Crawford, has done her hair and is applying extra make-up to make her look good for the signing ceremony that will mark the end of the conference.

11.30pm

As the Prime Minister arrives back at No 10, the staff clap and cheer; 1,000 red roses have arrived from a loyal supporter. 

She goes straight upstairs to see Denis. He advises her to withdraw from the race: 'Don't go on, love,' he says, but she is unconvinced.

Midday

In a meeting in Mrs Thatcher's study with her campaign team, they discuss what would happen if she withdrew. 

They agree that John Major would probably win the second ballot but not get enough votes to crush Michael Heseltine, therefore resulting in a third vote. 

The Prime Minister concludes that the right option is for her to stay in the fight.

2.30pm

As the Prime Minister leaves No10 to make a statement in the House of Commons on the outcome of the Paris conference, she shouts to waiting journalists: 'I fight on! I fight to win!'

4.45pm

In the Commons tearoom, Mrs Thatcher is shocked that MPs who were her supporters are irritated at her absence during the campaign. 

More than once she is told: 'Michael has asked me two or three times for my vote. This is the first time we have seen you.'

5pm

The Prime Minister phones John Major at home. 'Douglas is going to nominate me and I want you to second me,' she says bluntly. 

Major is put off by her assumption that she has his support, so he pauses and then says: 'If that is what you want, I will.' 

His hesitation irritates her. She wrote later with a hint of sarcasm: 'No doubt the operation on John's wisdom teeth was giving him trouble.'

6.15pm

Mrs Thatcher is in her office in Parliament meeting Cabinet members at five-minute intervals to ask them directly why she should stand down.

First in is Kenneth Clarke, Education Secretary. 

He sits on the sofa and tells the PM that any attempt to go into the second ballot would be 'like the Charge of the Light Brigade', doomed to failure, and that if she stood down either Douglas Hurd or John Major would be free to take on Michael Heseltine. 

She tells him bluntly that he is being defeatist.

6.30pm

Fourth on the sofa is Peter Brooke, the Secretary of State for Northern Ireland, who is in full evening dress, explaining that he had been told 'this was the correct wear when any serious decision was required of one'. 

Brooke says that she could win if she went ahead 'all guns blazing'.

7pm

Alan Clark speaks to Mrs Thatcher in between interviews. He thinks she looks 'calm, almost beautiful'. 

The Prime Minister says: 'It would be so terrible if Michael won. He would undo everything I have fought for.' 

Clark replies: 'Who the f**k's Michael? No one. Nothing. He won't last six months.' He urges her to fight right to the end.

7.30pm

All the interviews are over but the Cabinet ministers are still hanging around outside Mrs Thatcher's office. 

Chris Patten rubs his bottom and jokes: 'She gave me a good whacking!'

Inside her office, Norman Tebbit is consoling Mrs Thatcher, who is in tears. He said later she should have summoned the whole Cabinet and gone around the table asking who would back her, starting with the loyalists. 

'By the time she got to the rats, they would have been intimidated and they would have said: 'Yes, Prime Minister, of course we back you.' '

8.30pm

At their home, Norma Major is typing out a letter to Cranley Onslow, the Chairman of the 1922 Committee, saying that her husband is prepared to let his name go forward if the Prime Minister stands down.

11pm

Frank Field, a Labour MP but an admirer of Mrs Thatcher, arrives at No 10 and refuses to leave until he sees her. 

Field advises her to resign: 'You can't go out on a top note, but you can go out on a high note,' he says, and mentions that it will be hard to stop Heseltine becoming her successor.

The PM replies: 'He's a very bad man, Frank.' She suggests that it might be better for his reputation amongst his Labour colleagues if he left via the Cabinet Office exit.

11.30pm

Denis Thatcher and his daughter Carol are walking arm in arm across Horse Guards Parade towards the rear entrance of No 10, to avoid the cameras outside. Denis stops. 

He is weeping and says: 'Oh, it's just the disloyalty of it all.' It's the first time Carol has seen her father cry.

7.30pm, Thursday November 22

The Prime Minister rings Andrew Turnbull, her principal private secretary, to tell him she has decided to resign. 

He arranges an audience with the Queen for the afternoon. Calls are made to alert John Major and Douglas Hurd so their campaigns can begin.

8.05am

Denis Thatcher rings Carol: 'There have been all sorts of consultations and your mother …' Carol interrupts so he doesn't have to spell it out; she can hear the strain in his voice: 'I know, Dad.'

8.30am

The Cabinet is waiting outside the Cabinet Room, unaware of the PM's decision. John Major is still at home and there is speculation in Parliament and the Press that he is exaggerating the after-effects of his operation to avoid an awkward encounter with Mrs Thatcher.

Kenneth Clarke warns her campaign manager, John Wakeham, that he's prepared to make a fuss if she doesn't resign.

When Mrs Thatcher walks down the stairs, no one meets her gaze.

9.30am

A weeping Prime Minister announces to her Cabinet that she won't be standing again, reading from a statement: 'Having consulted widely among my colleagues, I have concluded that the unity of the Party and the prospects of victory in a general election would be better served if I stood down to enable Cabinet colleagues to enter the ballot for the leadership.'

She breaks down and can't say any more.

Cecil Parkinson jumps in, saying to the Lord Chancellor Lord Mackay: 'For Christ's sake, you read it.' But Mrs Thatcher says: 'I can read it myself.'

Some of the Cabinet are also in tears; others stare at the table.

After tributes are paid to her by Kenneth Baker and Douglas Hurd, Mrs Thatcher asks for no over-sentimental shows of sympathy. 'It's a funny old world,' she says.

One private secretary thinks it looks like watching Mary Queen of Scots being beheaded.

12.45pm

The Prime Minister is at Buckingham Palace giving formal notice of her intention to resign.

The Queen speaks so kindly to Margaret Thatcher that she leaves the Palace in tears.

4.50pm

At Prime Minister's Questions, Mrs Thatcher is in her element. The Prime Minister is asked if she will continue her fight against a European central bank when she leaves office.

Labour backbencher Dennis Skinner shouts out: 'No! She's going to be the governor!'

The PM's face lights up: 'What a good idea!' and then proceeds to attack a single currency as 'a federal Europe by the back door, so I'll consider the honourable gentleman's proposal. Now, where were we? I'm enjoying this!

A Tory MP shouts: 'Cancel it! her You can wipe the floor with these people!'

7pm

Carol phones her mother at No 10. 'I think you're a heroine! Your party are complete s***s.' Her mother replies calmly: 'Well, they've done what the Labour Party didn't manage to do in three elections: defeat me.'

4pm, Tuesday November 27

After a five-day leadership campaign between himself, Douglas Hurd and Michael Heseltine, John Major has returned to No 11 Downing Street having voted. 

Tired and apparently still not fully recovered from his wisdom tooth operation, he goes to bed.

Next door at No 10, the Thatchers' flat is full of packing cases and dustbin bags. Carol and her father are using their own cars to carry belongings to their newly-built home in Dulwich.

Carol recalled that while the Press outside were reporting how history was being made: 'Behind the curtains my mother was padding about in her stockinged feet deciding whether one layer of paper or two would be enough to protect her knick-knacks'.

6.25pm

A refreshed John Major is watching a television in the main reception room in No 11, together with Norma and his campaign team.

The result is clear: he has won 185 votes, Michael Heseltine 131, Douglas Hurd 56.

Heseltine and Hurd announce they will support Major in any third ballot.

Forty-seven-year-old John Major is the new leader of the Conservative Party.

Margaret and Denis walk through the connecting door from No 10 and she shakes the hand of Britain's new Prime Minister.

'Well done, John, well done,' she says, and then to Norma: 'It's what I've always wanted. The future is assured.'

Her son Mark was amazed: 'Power just transferred from one end of the room to the other.'

7.30am, Wed November 28

Mrs Thatcher walks downstairs from their flat to her study to check she hasn't left anything. She is shocked to find that her key for the door has already been removed from the keyring.

9.10am

The Downing Street staff are lined up in the entrance hall and burst into applause when Mrs Thatcher appears, wearing a burgundy suit, her hair immaculate. 

The former PM starts to cry.

Her assistant Cynthia Crawford checks that Mrs Thatcher's mascara hasn't smudged before she steps out to address the TV cameras. 

'We are leaving Downing Street for the last time in 11-and-a-half wonderful years, and we're happy that we leave the UK in a very, very much better state than when we came here …'

Once in the official car, the camera flashes capture tears in her eyes. Denis is holding her hand as they drive to the Palace to say farewell to the Queen.

Afterwards

After leaving No 10, the Thatchers had to adapt to a more ordinary life. Carol asked her mother if she would be able to manage a weekly shop in a supermarket. 

'Good heavens, yes, dear! I've opened enough of them.'

In 1992, she was made a Baroness. She later succumbed to dementia and died on April 8, 2013, aged 87, in a suite at the Ritz. 

Her death certificate described her as 'Stateswoman '.