Called to the Bar as an Advocate in 1970 and appointed as Queen's Counsel in 1985 he was elected as MP for Pentlands and represented that constituency from 1974 to 1997. Under Margaret Thatcher, he was appointed a Parliamentary Under Secretary of State and then, at the time of the Falklands War, he was transferred to the Foreign and Commonwealth Office, being promoted to Minister of State in 1983. He became a member of the Cabinet in 1986 as Secretary of State for Scotland. In 1990 he became Secretary of State for Transport and in 1992 Secretary of State for Defence. From 1995-97 he was Foreign Secretary. In 1997 he was knighted in recognition of his public service. Sir Malcolm was re-elected as a Member of Parliament in May 2005 for Kensington and Chelsea. He served as the Shadow Secretary of State for Work & Pensions and Welfare Reform until December 2005. He was re-elected in 2010, and now represents the new Kensington constituency. He was appointed by the Prime Minister to serve as Chairman of the Intelligence and Security Committee following the formation of the Coalition Government. He is a member of the Commonwealth Eminent Persons Group.