SDP, the
From Longman Dictionary of Contemporary EnglishSDP, thethe SDPSDP, the /ˌes diː ˈpiː/ noun the Social Democratic Party; a former political party in the UK, which was formed in 1981 by several important MPs (=Members of Parliament) from the Labour Party who believed that their party had become too left wing. It was led by Dr David Owen. Most of its members joined with the Liberal Party in 1987 to form the Social and Liberal Democrats (also called the Lib Dems ).