William Stephen Ian Whitelaw, 1st Viscount Whitelaw, (28 June 1918 – 1 July 1999) was a British Conservative Party politician who served in a wide number of Cabinet positions, most notably as Home Secretary from 1979 to 1983 and as de facto Deputy Prime Minister of the United Kingdom from 1979 to 1988. He was Deputy Leader of the Conservative Party from 1975 to 1991.
