Sir Mark Thatcher, 2nd Baronet (born 15 August 1953) is a British businessman and the son of Margaret, Lady Thatcher, former Conservative British Prime Minister, and Sir Denis Thatcher, 1st Baronet, and is the twin brother of Carol Thatcher. He has two children by his first wife, Diane Burgdorf; Michael Thatcher (who is heir apparent to the baronetcy), and Amanda Margaret Thatcher. He married his second wife, Sarah Jane Russell, daughter of Terry Clemence, a wealthy property developer, and sister of Viscountess Rothermere, in 2008.