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
Records of Prime Ministers of the United Kingdom to at least one other Prime Minister by blood or marriage. Two sets of father and son have successively held the office: The only brothers to hold the office were Henry Pelham, who was succeeded on his death in 1754 by the Duke of Newcastle. Pitt the Younger and Lord Grenville (who directly succeeded the latter in office) were the only set of full cousins to hold the office, their fathers being brothers-in-law. There have been three blood uncle-nephew sets of Prime Ministers: Lord Wilmington was two-greats uncle of Spencer Perceval, whose mother, Catherine ( Compton), Baroness Arden, was a