Edward George Geoffrey Smith-Stanley, 14th Earl of Derby (29 March 1799 – 23 October 1869) was a British statesman, three times Prime Minister of the United Kingdom, and to date the longest serving leader of the Conservative Party. He was known before 1834 as Edward Stanley, and from 1834 to 1851 as Lord Stanley. His record was unusual, since he is one of only four British Prime Ministers to have three or more separate periods in office. However his ministries all lasted less than two years, and totalled 3 years 280 days.