David William St John Heath CBE PC (born 16 March 1954) is a British optometrist and Liberal Democrat politician.He unsuccessfully contested Somerton and Frome at the 1992 General Election where he was defeated by the new Conservative MP Mark Robinson by 4,341 votes.Following the 2001 General Election he became a spokesman on work and pensions as well as serving as a member of the Science and Technology Select Committee.In March 2008 Heath was one of three Liberal Democrat spokesmen to defy the party whip and vote in favour of a referendum on the Treaty of Lisbon, for which he was sacked from his frontbench role.[3] In October 2008 he was given a partial reprieve when he was chosen to lead a Liberal Democrat commission on privacy in the UK,[4] and in January 2009 he was reappointed as spokesman on the office of the Leader of the House of Commons.