Records of Prime Ministers of the United Kingdom the middle name until the 1980s.) The richest Prime Minister was Lord Derby, with a personal fortune of over £7 million (about £444 million in today's money). The poorest was William Pitt the Younger, who was £40,000 (now over £1 million) in debt by 1800. Three Prime Ministers ultimately died as a result of accidents: Records of Prime Ministers of the United Kingdom The article lists the records of Prime Ministers of Great Britain and of the United Kingdom since 1721. The Prime Minister with the longest single term was Sir Robert Walpole, lasting 20 years and 315 days from
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