George Leggett was born in Warsaw in 1921, the son of Norman John Francis Leggett and Halina Henryka née Tuczyn. His father was a businessman, a director of the Alliance Assurance Company in Warsaw, and also held the position of British Honorary Vice Consul in Warsaw from 1924 onwards.

From childhood, George Leggett was bilingual in Polish and English. He was educated at home before being sent to school in England: first to St. Cyprian’s in Eastbourne, then Haileybury College in Hertfordshire. Leggett returned to Poland briefly in August 1939, leaving just before the German invasion. He obtained an open scholarship to Trinity Hall, Cambridge, to study French and German, beginning his studies in January 1940. Leggett spent five academic terms in Cambridge, achieving a First in part I of the Tripos in modern languages in summer 1941. He gained a BA degree under ‘War Emergency Regulations’ in February 1943 which was converted into an M.A. in 1952. Whilst at Cambridge Leggett also studied Russian as an extra-curricular subject, attending classes given by Dr. Elizabeth Hill, Lecturer in Russian, and taking tuition from Prince Dmitri Obolensky.

In August 1941, Leggett began working in the War Office and, though stationed in London, went to Oxford to attend a summer school in Oxford to learn Serbo-Croat. His linguistic skills led to his recruitment for the Yalta conference as administrative interpreter attached to Major Con Boddington of the War Office. In May 1945 Leggett was promoted acting Captain then in August 1945, Captain.

In June 1945 he was seconded to the War Cabinet Offices to act as administrative interpreter (in Russian) at the Potsdam Conference. However, because of his command of the Polish language he was "catapaulted into the centre of events when the Polish delegation arrived", interpreting for Churchill and Eden, then (after the 1945 General Election), for Attlee and Bevin.

After the end of the Second World War, Leggett returned to Berlin, working for the forces of occupation until 1947, then went on to a senior position in the Civil Service at the Ministry of Defence. In 1953, he married Rani Pamela Dandevi Evangelina Cragg, nee Birch, with whom he had a son, Richard. Rani had a son, Bill (1943-1991) from her first marriage, who became Leggett's stepson.

Leggett was retired early and, although he did not complete his PhD, he published his original research into Lenin's use of terror as "The Cheka: Lenin's Political Police".

George Leggett died on 1 May 2012.