Cavendish-Bentinck did not pursue a university education, instead entering the diplomatic service in 1915 at the age of 18 before taking leave to fight with the
Grenadier Guards in the
First World War, returning to the Foreign Office in 1919. In 1922, he took charge of administrative arrangements for the
Lausanne Conference. He served in the
British Embassy in
Paris and also in the
League of Nations Department in the
Foreign Office. Other postings included
Athens in 1932 and
Santiago in 1933. The high point of his diplomatic career came in 1939 when he was appointed chairman of the
Joint Intelligence Committee. He managed to develop the body as a highly effective instrument of government and, as a result, became counsellor to the Services Liaison Department of the Foreign Office in 1942. However, he cast doubt on reports that were received regarding the Nazi genocide of the Jews. In late August 1943 the Polish Embassy in London informed the British government of the deportation and annihilation of hundreds of thousands of Jews from Lublin and Bialystok provinces. As chairman of the Joint Intelligence Committee, Victor Cavendish-Bentinck hesitated to believe Polish and Jewish information about atrocities. Rather, he viewed the information as an attempt to 'stoke us up.' He added: 'I feel certain that we are making a mistake in giving credence to this gas chamber story.' In 1945, Cavendish-Bentinck was given his final diplomatic posting on his appointment as
Ambassador to Poland. When visiting the formerly German City of
Stettin (Szczecin) in 1946 he was invited to talk to German civilians suffering from months of
internment so their
possessions and property could be taken over by Polish resettlers from territories lost to the
USSR. Cavendish-Bentinck refused to do so, ignoring certain inhuman circumstances under which mainly old people, women and children had to suffer, by noting to his Polish hosts, he was "convinced that they will complain as usual". He held the position for two years before the Foreign Office applied to appoint him
Ambassador to Brazil. He never took up the latter post, being obliged to resign from the Foreign Office, without a pension, as a result of the publicity surrounding his divorce. Bentinck's aristocratic background attracted press attention; Foreign Secretary
Ernest Bevin, apparently sympathetic, remarked at that the time "I could have saved him if his name had been Smith." ==Later life and Duke of Portland==