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 10 February 1746 but returned to office two days later (12 February) when Lord Bath had been invited to form a ministry but failed to do so. The shortest interval where an intervening ministry had been formed was achieved by Lord Melbourne, who was out of office after being dismissed on 14 November 1834 but returned following the end of successor Sir Robert Peel's first ministry on 18 April 1835155 days (under six months) later. Of all Prime Ministers, only two have been female. Both were Conservative Party leaders. Two Prime Ministers were born in Ireland: Bonar Law was born