Sir Alan James Beith PC (born 20 April 1943) is a British politician who represented the constituency of Berwick-upon-Tweed as its Member of Parliament (MP) from 1973 until 2015. From 1992 until 2003 he was Deputy Liberal Democratic Party Leader and, by 2015, Sir Alan was the longest-serving of his party sitting in the House of Commons and the last Liberal Democrat//Liberal MP to have experience of Parliament from the 1970s.