The Marquess of Salisbury was elected the Conservative Member of Parliament for South Dorset in 1979 and served until 1987, when he did not stand for re-election. During these eight years he was particularly interested in foreign affairs, constitutional affairs and Northern Ireland. He was summoned to the Upper House as Baron Cecil of Essendon, in the County of Rutland, by a Writ of Acceleration in 1992. He became a Life Peer in November 1999. From 1992 to 1994 he was Parliamentary Under-Secretary of State for Defence, from 1994 to 1997 he was Lord Privy Seal and Leader of the House of Lords, and from 1997 to 1998 he was Leader of the Opposition in the House of Lords. He took leave of absence from the House of Lords in 2002.