Portland Place is a street in the Marylebone district of central London. Named after the 3rd Duke of Portland, the unusually wide street is home to the BBC's headquarters Broadcasting House, the Chinese and Polish embassies, the Royal Institute of British Architects and numerous residential mansion blocks.

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 was also the fourth great-grandfather of King Charles III through his great-granddaughter Cecilia Bowes-Lyon, Countess of Strathmore and Kinghorne.