Records of Prime Ministers of the United Kingdom Wilmington to Theresa May) University college with most alumni Prime MinistersChrist Church, Oxford13 (George Grenville to Sir Alec Douglas-Home) Vocational institution with most Prime Ministers as studentsThe Inns of Court11 (Lord Wilmington to Tony Blair). Of these, eight passed through Lincoln's Inn (William Pitt the Younger to Tony Blair). The first Prime Minister never to have been a university graduate was the Duke of Devonshire (served 1756–57), the last (as of ) was John Major (served 1990–97). The earliest Prime Minister to be an armed forces veteran was Henry Pelham, Prime Minister in 1743–54, who had served as a volunteer
Historical rankings of Prime Ministers of Canada <nowiki>^</nowiki> Served less than 2 years, 3 months, as Prime Minister, while all others served for more than 4 years, 11 months. William Lyon Mackenzie King (photo) is the highest rated prime Minister based on three aggregate results from Maclean's The Institute for Research on Public Policy undertook a survey to rank the prime ministers who had served in the 50 years preceding 2003. They ranked those nine prime ministers as follows: <nowiki>^</nowiki> Served less than 10 months as Prime Minister, while all others served for more than 4 years, 11 months. In October 2016, Maclean's again ranked the prime