<P> The Prime Minister with the longest period between the start of their first appointment and the end of their final term was the Duke of Portland, whose first term began on 2 April 1783 and whose second and final term ended on 4 October 1809 . </P> <P> A Prime Minister's "term" is traditionally regarded as the period between their appointment and resignation, dismissal (or death, in the case of those who die in office), with the number of general elections taking place in the intervening period making no difference . </P> <P> The only Prime Minister to serve four terms under that definition was William Ewart Gladstone (3 December 1868--20 February 1874, 23 April 1880--23 June 1885, 1 February 1886--25 July 1886 and 15 August 1892--5 March 1894). </P> <P> The office of Prime Minister has coincided with the reigns of 11 British monarchs (including a Regency during the incapacity of George III from 1811 to his death in 1820), to whom the Prime Minister has been constitutionally head of government to the sovereign's headship of state . </P>

Who has been prime minister the most times