He won more elections than any other 20th century Prime Minister of the United Kingdom ( in 1964 , 1966 , February and October 1974 ) â '' but only once with a clear majority ( 1966 ) . He emerged as Prime Minister after more general elections than any other 20th century premier , contesting five general elections and winning four of them ( in 1964 , 1966 , February 1974 and October 1974 ) .