Margaret Thatcher's tenure as Prime Minister of the United Kingdom began on 4 May 1979 when she accepted an invitation from Queen Elizabeth II to form a government, succeeding James Callaghan of the Labour Party, and ended on 28 November 1990 upon her resignation.

[3] She emphasised reducing the government's role and letting the marketplace decide in terms of the neoliberal ideas pioneered by Milton Friedman and Friedrich Hayek, promoted by her mentor Keith Joseph, and promulgated by the media as Thatcherism.

[7] Thatcher, having to share the media spotlight with Queen Elizabeth II and Diana, Princess of Wales,[b] increasingly assumed regal poses, such as taking the salute at the victory parade after the Falklands War, and becoming the centre of attraction on foreign visits.

Thus Thatcher's refusal to recognise the Muzorewa government ultimately allowed Mugabe to take power, an outcome that outraged whites in Rhodesia but which satisfied British opinion and was applauded internationally.

According to Robert Matthews, the success of the Lancaster House negotiations can be explained by four factors: A balance of forces on the battlefield that clearly favoured the nationalists; international sanctions and their adverse effects on Rhodesia's economy and Salisbury's ability to wage war; a particular pattern of third party interests; and finally, the skill and resources that Lord Carrington as mediator brought to the table.

[35] In the words of one historian: The mood reflected Mrs Thatcher's Iron Lady stance, her proclaimed intention of laying the "Suez Syndrome" to rest and again projecting Britain as a great power.

Thatcher recognised that Soviet hegemony was vulnerable in Poland and offered public support for Lech Wałęsa and his Solidarity labour union, in close co-operation with the United States and Pope John Paul II (a long-time leader of Polish Catholicism).

[42][page needed] Victory brought a wave of patriotic enthusiasm and contributed to Thatcher's re-election, with one poll showing that 84% of the electorate approved of the Prime Minister's handling of the crisis.

Just as the victory in the Falklands War exorcised the humiliation of Suez, so the eventual defeat of the NUM etched in the public mind the end of militant trade unionism which had wrecked the economy and twice played a major part in driving elected governments from office."

[61][page needed] The National Coal Board received the largest amount of public subsidies going to any nationalised industry: by 1984 the annual cost to taxpayers of uneconomic pits had reached £1 billion.

[62]: 143–4, 161  The year-long confrontation over strikes carried out from April 1984 by the National Union of Mineworkers (NUM), in opposition to proposals to close a large number of unprofitable mines, proved a decisive victory for Thatcher.

The Government had made preparations to counter a strike by the NUM long in advance by building up coal stocks, keeping many miners at work, and co-ordinating police action to stop massive picketing.

More and more frustrated miners resigned to the impending failure of the strike and, worn down by months of protests, began to defy the union's rulings, starting splinter groups and advising workers that returning to work was the only viable option.[65]: ch.

[73] In February 1985, in what was generally viewed as a significant snub from the centre of the British establishment,[74] the University of Oxford voted to refuse Thatcher an honorary degree in protest against her cuts in funding for higher education.

[101][68]: 23–26, 594–5 [102]: 252–53 In the aftermath of a series of terrorist attacks on US military personnel in Europe, which were believed to have been executed at Colonel Gaddafi's command, President Reagan decided to carry out a bombing raid on Libya.

[111] In July 1985, Thatcher, citing the support of Helen Suzman, a South African anti-apartheid MP, reaffirmed her belief that economic sanctions against Pretoria would be immoral because they would make thousands of black workers unemployed; instead she characterised industry as the instrument that was breaking down apartheid.

[123] "The key change from earlier attempts was that, for the first time in the checkered history of the Tunnel project, there was a British Prime Minister who was strongly in favour of it, and applied all the drive of her formidable personality to see it through."

[129][page needed] Her resolute personality played a key role in overcoming the well-organised, media-wise Labour campaign led by Neil Kinnock, who was weakened by his party's commitment to unilateral nuclear disarmament at a time Thatcher was helping to end the Cold War.

At a meeting before the European Community summit in Madrid in June 1989, Lawson and foreign secretary Geoffrey Howe forced Thatcher to agree to the circumstances under which she would join the Exchange Rate Mechanism.

[50]: 712  Thatcher responded by moving Howe to Leader of the House of Commons (despite giving him the title Deputy Prime Minister he was now effectively removed from decision-making over Europe) and by listening more to her adviser Sir Alan Walters on economic matters.

Thatcher continued to be the leading international advocate of a policy of contact with apartheid South Africa,[149] and the most forthright opponent of economic sanctions against the country, which a white minority government ruled.

[160] However her call to the world to reward reforms was countered by Mandela himself, who while still in jail argued sanctions must be maintained until the end of white rule,[150] and criticised her decision to lift a ban on new investment unilaterally.

[165] Thatcher's opposition to sanctions left her isolated within the Commonwealth and the European Community, and Mandela did not take up an early offer to meet her,[166] opposing her proposed visit to his country as premature.

[170][171] Their first meeting failed to resolve differences over her unilateral lifting of sanctions and his refusal to renounce armed struggle until existing conditions for the black majority in South Africa changed.

[172] In their economic discussions, Mandela initially favoured nationalisation as a preferred method for redistributing wealth between blacks and whites, but with British investment in South Africa in 1989 accounting for half of the total, and with bilateral trade worth just over $3.2 billion,[172] Thatcher successfully urged him to adopt free-market solutions, arguing they were necessary to maintain the kind of growth that would sustain a liberal democracy.

Thatcher sought to relieve what she considered the unfair burden of property tax on the property-owning section of the population and outlined a fundamental solution as her flagship policy in the Conservative manifesto for the 1987 election.

[182] "What remains to be explained is why a politician who had hitherto shown such brilliant populist sensitivity should destroy herself with a tax reform which inflicted terrible damage on millions of people who had been in the front line of the Thatcher Revolution ...

Shortly afterwards, her staff made public what was, in effect, her resignation statement, in which she stated that she had "concluded that the unity of the Party and the prospects of victory in a General Election would be better served" if she stood down as prime minister.

Leader of the Opposition Neil Kinnock proposed a motion of no confidence in the Government, and Margaret Thatcher seized the opportunity this presented on the day of her resignation to deliver one of her most memorable performances.

These include: Papers released in December 2014 show that Thatcher completely disapproved of GCSEs which, in 1986, Sir Keith Joseph was trying to introduce in the face of fierce opposition from teaching unions.