At 6.30am, two men arrived at the gates of Downing Street asking to be let in to see the Prime Minister. The policeman on the gate phoned through to Charles Powell, who was already at his desk. The two turned out to be Tory backbenchers Michael Brown and Edward Leigh. Powell gave them coffee and explained the PM was dressing and asked them to wait. They waited and waited – in vain. They were still there when the Cabinet convened at 9am. They were put out of their misery only when the PM's political secretary John Whittingdale told them what they had already guessed. She was resigning. Tears streamed down Brown's face as he left No 10 by a back door, thus avoiding waiting TV cameras in Downing Street.
At 7am, Cecil Parkinson was barely awake. The shrilling of the telephone put paid to that. It was Chris Chope, one of his junior ministers and a key member of the No Turning Back Group. "She's going," he said. "You've got to do something." Parkinson had last seen the PM at 6pm the previous evening, before her confidence had been shattered by the meetings with her cabinet members. So confident was he that she was heading for victory, and that the Cabinet was supporting her, he went out to dinner with his wife and some friends. A few hours earlier, The Sun's Trevor Kavanagh had got wind of what was about to happen and had rung the Parkinson house to check if he knew anything. Parkinson had already gone to bed and his wife Ann, a close friend of the PM, said she didn't want to wake him. Had she done so, Parkinson would have hot-footed it to Downing Street.
After Chope's phone call, Parkinson immediately phoned No 10, only to be told that the PM was under the hair dryer and that he should phone back in 30 minutes. In desperation, he then phoned his friend of 20 years' standing, Norman Tebbit. Tebbit had been with her until late the previous night working on her speech for the Censure debate. He told Parkinson the game was up and that her mind would not be changed. Parkinson decided it was pointless to phone No 10 again.
By 7.30am, Andrew Turnbull had been at his desk for an hour already. He sat there unable to concentrate. He spoke to the Prime Minister several times a day, but he knew their next conversation would probably be a fairly momentous one. The call came. It was the news he had expected, as the Prime Minister asked him to put in place the formal arrangements for her resignation announcement. The next call he made was to the Palace to arrange for the formalities of an audience with the Queen.
Woodrow Wyatt called in a last-ditch attempt to make the PM change her mind, but for once, she wouldn't take his call. In fact, she didn't take calls from anyone until after the Vote of Censure debate was over, later in the afternoon.
Peter Morrison phoned Douglas Hurd and John Major to advise them of the Prime Minister's decision. John Wakeham and Kenneth Baker were also tipped off by Morrison. Shortly after 8am, Denis Thatcher phoned his daughter. "There have been all sorts of consultations and your mother ..." Carol interrupted him. "I know, Dad." Nothing further was said.
At 8.30 every Thursday morning, it was usual for the Prime Minister to hold a short briefing in preparation for Prime Minister's Questions. As usual, Bernard Ingham, Charles Powell and John Whittingdale were with her. It was a subdued meeting and no one was really concentrating.
The regular Thursday cabinet meetings were a matter of routine for most of those who attended them. This one was different. Cabinet meetings normally start at 10.30am, but this one had been brought forward so as not to clash with a memorial service for Lady Home, which was to be held later in the morning at St Margaret's Church. Normally, the Cabinet would gather for coffee 15 minutes before the meeting and gossip about the latest political machinations, before the Prime Minister would rush into the room, apparently always in a hurry. That was the signal for the rest of them to take their seats around the famous oval table.
But on this morning the atmosphere was strained to say the least. The few remaining Thatcher loyalists eyed up the rest of their cabinet colleagues and could barely bring themselves to speak. In her memoirs, Margaret Thatcher recalls: "They stood with their backs against the wall looking in every direction except mine." According to Cecil Parkinson, Kenneth Clarke was the only one who was showing the remotest sign of life, telling "anybody who cared to listen that if the PM did not resign before noon that day, he would do so himself".
Thatcher's arrival was normally the signal for everyone to file into the room and take their places, but it seemed there was a delay. John MacGregor had been held up in traffic. The awkward silence continued for an unbearable 10 minutes. At 9.10, the Cabinet filed in. The PM was in her usual chair, halfway along the table in front of the fireplace. They took their places in silence – even the sound of the chairs being pulled back seemed to grate. For the first time in living memory, the woman who had dominated her Cabinet for 11 years seemed powerless. The aura had gone. Still, there was silence. Cecil Parkinson noticed her reddened, swollen eyes. A carton of tissues sat next to her on the table. While the cabinet members were taking their seats, she picked a tissue and dabbed her eyes. The dreadful silence continued. Slowly, Margaret Thatcher opened her handbag and pulled out a creased piece of paper. The Cabinet knew what was coming, but the performance had to be played out nonetheless. She read in a slow, halting, and emotional manner:
"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. I should like to thank all those in the Cabinet and outside who have given me such dedicated support."
She faltered several times and broke down sobbing. She wasn't the only one. David Waddington, Tony Newton, John Gummer, Michael Howard and John Wakeham were all in tears. Cecil Parkinson later wondered why Mr Wakeham should be so upset, when it was he, in Parkinson's opinion, who had largely brought about the events they were witnessing.
Halfway through the statement she was so upset that Cecil Parkinson, already on a light fuse, shouted to the Lord Chancellor, who was sitting to her left: "For Christ's sake, you read it, James." Lord Mackay briefly put his arm round her shoulder and said gently, "Let me read it, Prime Minister." This brief interjection broke the unbearable tension and allowed the Prime Minister a few moments to gather herself. She stiffened both in resolve and body language and said, "No! I can read it myself."
Norman Lamont recalls her "referring to the events of the last few days and to the advice she had had 'from so many of you' that she could not win and should not fight on. The way she put it implied that she did not agree and thought us spineless". It was after these words that the worst breakdown occurred.
James Mackay, the Lord Chancellor, then read out a short tribute to the Prime Minister. She listened, eyes glistening and red, and broke down again. She regained composure and told the Cabinet it must unite behind a candidate to beat Michael Heseltine. "We must protect what we believe in," she flashed.
Kenneth Baker then spoke in his capacity as chairman of the party. "You have and will always continue to have the love and loyalty of the party. You have a very special place in the heart of the party. You have led us to victory three times and you would have done so again. Those who have served you recognise that they have been in touch with greatness." He, also, was close to tears.
Douglas Hurd referred to this "whole wretched business" and said he wanted to put on record the superb way in which the Prime Minister had conducted business at the Paris conference, particularly the pressures of the leadership election.
The Prime Minister then called a halt, saying she could deal with routine matters but not sympathy. She was still in a highly emotional state and felt she might lose her composure entirely if such tributes went on for much longer. She ended proceedings by telling the Cabinet that any new leader would have her total and devoted support. It was assumed this did not include Michael Heseltine. "Well, now that's out of the way, let's get on with the rest of the business," she said.
The meeting broke for 10 minutes and coffee was served. Courtesy calls were made to the other party leaders and the Speaker. The atmosphere was considerably lighter. A formal statement was issued by the Downing Street Press Office at 9.25.
The Cabinet resumed and skimmed through the rest of the normal agenda by 10.15. Douglas Hurd's mind was elsewhere, though. He knew that events would move fast. Kenneth Baker passed a note to Hurd asking if he had come to an agreement with John Major about the candidacy. Hurd sent a note back saying they were issuing a joint statement declaring that they had worked closely together in the past but the best way of uniting the party was to let both their names go forward in the next ballot. He then passed the draft statement to Baker who regarded it as a "perfectly masterful composition". Hurd then tried to catch Tom King's eye to ask if he would act as his proposer on the second ballot. King didn't get the hint.
By the close of the meeting, the Prime Minister was close to tears again. She invited ministers to stay behind for yet more coffee. By now she was fully composed and was keen to know her colleagues' views on what might happen in the second ballot.
No one was keen to be the first to leave, although Douglas Hurd didn't hang around long. Cecil Parkinson's most vivid memory was when somebody – allegedly Kenneth Clarke – said: "We are going to pin regicide on Heseltine." For a moment the PM looked puzzled and issued a devastating reply: "Oh no, it wasn't Heseltine; it was the Cabinet." Parkinson says this was said without the slightest hint of rancour. "It was, to her, a simple statement of fact," he says.
Douglas Hurd, however, had other things on his mind and left immediately. Norman Lamont caught Michael Howard's eye. They were both anxious to go. While Heseltine was out there campaigning, important time was being lost. After what seemed an age, Margaret Thatcher sensed what others were thinking and told everyone to leave and "stop Heseltine".
As the Cabinet left Downing Street, Kenneth Baker made a short statement outside No 10: "This is a typically brave and selfless decision by the Prime Minister. Once again Margaret Thatcher has put her country and the party's interests before personal considerations. This will allow the party to elect a new leader to unite the party and build upon her immense successes. If I could just add a personal note, I am very saddened that our greatest peace-time Prime Minister has left government. She is an outstanding leader, not only of our country but also of the world. I do not believe we will see her like again."
John Wakeham followed suit. Asked about her mood, he said: "Well, her mood is, like always, she does her duty, she's – of course she's sad." It was rather an understatement. While Denis attended the memorial service for Lady Home, the Prime Minister was driven to Buckingham Palace, informing the Queen in person of her decision to resign. It was not a long audience. The Prime Minister was well aware she had the speech of her life to make in the House of Commons in just a few hours' time. It was to be an occasion she, and the country, would have cause to remember for many years to come.
'Margaret Thatcher: In Her Own Words' by Iain Dale is published by Biteback in paperback, £12.99 and in a three-CD box set at £19.99
The key players: Who were they, and where are they now?
The Prime Minister's private secretary. Worked for John Major before career in business. Ennobled in 2000.
Tory MP 1979-97. Now an independent political columnist.
Tory MP since 1983. Chaired the influential Public Accounts Committee for nine years. Now a Treasury financial adviser.
Thatcher's loyal political secretary. Became MP in 1992. Chairs the Culture, Media and Sport Select Committee.
Thatcher's Transport Secretary. Stood down as an MP in 1992 and joined the House of Lords. Was party chairman in 1997-98.
First elected in 1983. Junior minister to introduce poll tax. Defeated in 1992 but regained a seat in 1997.
Quit front bench in 1987 to care for his wife, severely injured in IRA Brighton bomb. Ennobled in 1992. Prolific writer and blogger.
Thatcher's principal private secretary. Went on to become Cabinet Secretary.
A former Labour MP, later became an admirer of Thatcher. Newspaper columnist and chairman of the Tote. Died in 1997.
Tory MP 1974-92. Was PM's parliamentary aide in 1990 and led her campaign to remain leader.
Foreign Secretary when she stood down – a role he continued under Major until 1995. Ennobled in 1997.
Chancellor under Thatcher. Defeated Michael Heseltine and Douglas Hurd with Thatcher's support to become youngest PM for more than 100 years. Won 1992 election but resoundingly defeated in 1997. Remained MP until 2001. Refused peerage.
Energy Secretary under Thatcher and Major. Became a peer in 1992; Leader of the House of Lords until 1994.
Tory party chairman 1989-90. Promoted to Home Secretary under Major. Quit the Government in 1992 and the Commons for the Lords in 1997.
PM's much-mocked husband. Self-described as "honest-to-God right-winger". Died in 2003.
Prime Minister's daughter. Won I'm a Celebrity... Get Me Out of Here! in 2005.
Journalist turned civil servant. Thatcher's chief press secretary 1979-90. Knighted in her resignation honours list, now a columnist.
Health Secretary in Thatcher's final cabinet. Home Secretary and Chancellor under Major. After three doomed leadership bids, retired to back benches before being appointed Justice Secretary in David Cameron's coalition government.
Made Leader of the Commons days before Thatcher's resignation. Later Major's Transport Secretary. Left the Commons for the Lords in 2001.
Thatcher's last Home Secretary; moved to the Lords when Major became leader.
Social Security Secretary under Thatcher and Major, defeated in 1997 and joined the Lords.
Party chairman and later Agriculture Minister under Thatcher, promoted to Environment Secretary by Major. Left the Commons in May, and joined the Lords.
Thatcher's last Employment Secretary; served in Major's Cabinet including Home Secretary. Elected Tory leader in 2003, leading them to historic third defeat in 2005, before retiring to the back benches. Retired as an MP in May 2010, and joined the Lords.
Scottish advocate served as Lord Chancellor from 1987-97.
Thatcher's Treasury Chief Secretary. As Major's Chancellor oversaw disastrous Black Wednesday and Britain's withdrawal from the ERM, with a young David Cameron advising. Quit government after Major tried to demote him. Left the Commons in 1997. Became Lord Lamont of Lerwick in 1998.
Quit as Thatcher's Defence Secretary over the Westland affair to sit on the back benches. Major's Trade and later Environment Secretary before becoming Deputy Prime Minister in 1995. Ennobled in 2001. Head of coalition's £1.4bn regional growth fund.
Long-serving cabinet minister, was Defence Secretary when Thatcher quit and continued under Major during Gulf War. Left Commons and joined the Lords in 2001.