Heath government, 1970–1974

When the Conservatives returned to power in 1970 under Edward Heath, Whitelaw was made Lord President of the Council and Leader of the House of Commons, with a seat in the cabinet.^[15] Upon the imposition of direct rule in March 1972, he became the first Secretary of State for Northern Ireland, serving in that capacity until November 1973. During his time in Northern Ireland he introduced Special Category Status for paramilitary prisoners. He attempted to negotiate with the Provisional Irish Republican Army, meeting its Chief of Staff Seán Mac Stiofáin in July 1972. The talks ended in an agreement to change from a seven-day truce to an open-ended truce; however, this did not last long. As a briefing for prime minister Heath later noted, Whitelaw "found the experience of meeting and talking to Mr Mac Stíofáin very unpleasant". Mac Stiofáin in his memoir complimented Whitelaw, saying he was the only Englishman ever to pronounce his name in Irish correctly.^[16]

In 1973, Whitelaw left Northern Ireland—shortly before the Sunningdale Agreement was reached—to become Secretary of State for Employment, and confronted the National Union of Mineworkers over its pay demands. This dispute was followed by the Conservative Party losing the February 1974 general election.^[17] Also in 1974, Whitelaw became a Member of the Order of the Companions of Honour.^[18]

In opposition, 1974–1979

Soon after Harold Wilson's Labour Party returned to government, Heath appointed Whitelaw as deputy leader of the opposition and chairman of the Conservative Party. Following a second defeat in the October 1974 general election, during which Whitelaw had accused Wilson of going "round and round the country stirring up apathy", Heath was forced to call a leadership election in 1975. Whitelaw loyally refused to run against Heath; however, and to widespread surprise, Margaret Thatcher narrowly defeated Heath in the first round. Whitelaw stood in his place and lost convincingly against Thatcher in the second round. The vote polarised along right–left lines, with in addition the region, experience and education of the MP having their effects.^[19]

Whitelaw managed to maintain his position as deputy leader until the 1979 general election, when he was appointed Home Secretary. In an unofficial capacity,^[2] he also served as Deputy Prime Minister in Thatcher's new government.^[3][20]

Home Secretary, 1979–1983

Thatcher admired Whitelaw and appointed him Home Secretary in her first Cabinet, later writing of him "Willie is a big man in character as well as physically. He wanted the success of the Government which from the first he accepted would be guided by my general philosophy. Once he had pledged his loyalty, he never withdrew it".^[21] Thatcher was rumoured to have said that "every Prime Minister needs a Willie" and Whitelaw was seen as Thatcher's de facto Deputy Prime Minister between 1979 and 1988 (though he never formally held the office), to the extent that the then Cabinet Secretary, Robert Armstrong, said that had Thatcher been killed in the Brighton hotel bombing, he thought he would have advised Queen Elizabeth II to send for Whitelaw.^[22][23][24]

As home secretary, Whitelaw adopted a hard-line approach to law and order. He improved police pay and embarked upon a programme of extensive prison building. His four-year tenure in office, however, was generally perceived as a troubled one. His much vaunted "short, sharp shock" policy, whereby convicted young offenders were detained in secure units and subjected to quasi-military discipline, won approval from the public but proved expensive to implement. He was home secretary during the six-day Iranian Embassy siege in April–May 1980.

In March 1981, he approved Wolverhampton Metropolitan Borough Council's 14-day ban on political marches in the borough in response to a planned National Front demonstration there.^[25]

Inner city decay, unemployment and what was perceived at the time as heavy-handed policing of ethnic minorities (notably the application of what some called the "notorious" sus law) sparked major riots in London, Liverpool, Birmingham and Leeds, and a spate of disturbances elsewhere. The Provisional IRA escalated its bombing campaign in England.

He contemplated resigning after an intruder broke into the Queen's bedroom in 1982 but was dissuaded from doing so. "We couldn't do without Willie," Margaret Thatcher reflected in later years. "He was a wonderful person."^[26]

Leader of the House of Lords, 1983–1988

Two days following the 1983 general election, Whitelaw received a hereditary peerage (the first created for 18 years) as Viscount Whitelaw, of Penrith in the County of Cumbria.^[27] Thatcher appointed him Lord President of the Council and Leader of the House of Lords. Lord Whitelaw faced many challenges in attempting to manage the House of Lords, facing a major defeat over abolition of the Greater London Council within a year of taking over. However, his patrician and moderate style appealed to Conservative peers and his tenure is considered a success.

During his period as her deputy and as Leader of the Lords, Thatcher relied on Whitelaw heavily; she famously announced that "every prime minister needs a Willie".^[28] He chaired the "star chamber" committee that settled the annual disputes between the limited resources made available by Treasury and the spending demands of other government departments. It was Whitelaw, in November 1980, who managed to dissuade Thatcher from going to Leeds to take charge of the Yorkshire Ripper investigation personally.^[29]

Resignation

Following a stroke in December 1987, he felt he had no choice but to resign. Nicholas Ridley argued that Whitelaw's retirement marked the beginning of the end of the Thatcher premiership, as he was no longer around as often to give sensible advice and to moderate her stance on issues, or to maintain a consensus of support in her own Cabinet and parliamentary party. He resigned from the Cabinet on 10 January 1988.^[30]