Asquith, 1886 - 1908 - 22 years
George, 1890 - 1916 - 26 years
Bonar Law, 1900 - 1922 - 22 years
Baldwin, 1908 - 1923 - 15 years
MacDonald, 1906 - 1924 - 18 years
Chamberlain, 1918 - 1937 - 19 years
Churchill, 1900 - 1940 - 40 years
Attlee, 1922 - 1945 - 23 years
Eden, 1923 - 1955 - 32 years...