William Cavendish-Bentinck, 3rd Duke of Portland, English politician, Prime Minister of the United Kingdom (born 1738)

William Henry Cavendish Cavendish-Bentinck, 3rd Duke of Portland was a British Whig and then a Tory politician during the late Georgian era. He served as chancellor of the University of Oxford (1792–1809) and as Prime Minister of Great Britain (1783) and then of the United Kingdom (1807–1809). The gap of 26 years between his two terms as prime minister is the longest of any British prime minister. He is also an ancestor of King Charles III through his great-granddaughter Cecilia Bowes-Lyon, Countess of Strathmore and Kinghorne.

The prime minister of the United Kingdom is the head of government of the United Kingdom. The prime minister advises the sovereign on the exercise of much of the royal prerogative, chairs the Cabinet, and selects its ministers. Modern prime ministers hold office by virtue of their ability to command the confidence of the House of Commons, so they are invariably members of Parliament.

October 30 is the 303rd day of the year in the Gregorian calendar; 62 days remain until the end of the year.