Deborah Vivien Cavendish, Duchess of Devonshire (née Deborah Freeman-Mitford; 31 March 1920 – 24 September 2014) was a British writer and aristocrat. He was the youngest and last living member of the six Mitford sisters. The sisters were a figure of political connections and promiscuity were a famous feature of English culture in the 1930s and 1940s.