The Chancellor and Under-Treasurer of Her Majesty's Exchequer, commonly known as the Chancellor of the Exchequer, or simply the Chancellor, is a senior official within the Government of the United Kingdom and head of Her Majesty's Treasury. The office is a British Cabinet-level position.

During Margaret Thatcher's time as the British Prime Minister there was three people who held the role of Chancellor of the Exchequer. The first was Geoffrey Howe from 4 May 1979 until 11 June 1983. The third was John Major who held the post from 26 October 1989 until 28 November 1990. Nigel Lawson held the post for the longest period from 11 June 1983 until 26 October 1989. Norman Lamont did not serve as Chancellor of the Exchequer for Margaret Thatcher.

Nigel Lawson, Baron Lawson of Blaby, PC (born 11 March 1932) is a British Conservative politician and journalist. He was a Member of Parliament representing the constituency of Blaby from 1974 to 1992, and served in the cabinet of Margaret Thatcher from 1981 to 1989. Prior to entering the Cabinet, he served as the Financial Secretary to the Treasury from May 1979 until his promotion to Secretary of State for Energy. He was appointed as Chancellor of the Exchequer in June 1983, and served until his resignation in October 1989.

More Info: en.wikipedia.org