From 1922 the Labour Party had a recognised leader so took over all remaining commons opposition roles from the Opposition Liberal Party. Since 1922 the principal Government and Opposition parties have been the Labour Party and the Conservative Party. There were three instances of peers being seriously considered for the prime ministership, during the twentieth century (Curzon of Kedleston in 1923, Halifax in 1940 and Home in 1963), but these were all cases where the Conservative Party was in government and do not affect the list of leaders of the opposition.