Social Democratic party

Social Democratic party (SDP), former British political party founded in 1981 to offer a centrist alternative to the more extreme positions of the then ruling Conservative party on the right and the opposition Labour party on the left. The SDP began with the defection of 12 Labour members of Parliament who opposed their party's leftward drift. The party joined in an electoral alliance with the Liberal party in 1981 and merged with the Liberals in 1988 to form the Social and Liberal Democratic party, now the Liberal Democrats . Some SDP members re-formed the party in 1988, but they disbanded in 1990.

Social Democratic Party (SDP) Political party in England (1981–90), centrist in political outlook. At the general elections of 1983 and 1987, the party joined forces with the Liberal Party to create the Liberal-SDP Alliance. By the second election, however, the two parties were already in the process of merging to form the Liberal Democrats.

Social Democratic Party (SDP) (UK) A political party formed in March 1981 by four leading politicians (the ‘Gang of Four’) from the right of the Labour Party: Roy Jenkins, David Owen, Bill Rodgers, and Shirley Williams. It reflected their general concern that Labour had become too left-wing, and their specific opposition to Labour's support of withdrawal from Europe, and its endorsement of unilateral nuclear disarmament (CND). It advocated policies associated with the centre ground of British politics, such as a mixed economy, but also argued for more radical measures such as Scottish devolution. The party began with fourteen MPs, but doubled this number before the 1983 general election, owing to by-election successes and defections. It soon formed an Alliance with the Liberal Party, and made much headway in local politics. However, the first-past-the-post electoral system prevented the party from making a decisive breakthrough in Parliament. After the 1987 general election, the Alliance split. The two parties of the Alliance merged in 1988 to form the Liberal Democrats. However, three MPs soldiered on for a separate SDP, including Owen himself, though none stood for re-election in 1992.