Sir Mark Thatcher, 2nd Baronet (born 15 August 1953) is the only son of Sir Denis Thatcher and Baroness Thatcher, the former British Prime Minister, and twin brother of Carol Thatcher. In addition to his prominence as the only son of one of the world's best known politicians, Sir Mark has attracted headlines for his early youthful playboy lifestyle, involvement in motorsports, business associations, and for the role he played in an attempted coup in Equatorial Guinea.