The Jaques family were predominantly non-theatrical, with the exception of Mary who appeared in the small role of Harry Hathaway in the Christmas pantomime "Robinson Crusoe" at the Palace Theatre, Cologne, in 1920. Mary enjoyed the theatre, and took Jacques to live performances from an early age. The result had a "profound effect" on the young girl, particularly a love of dance. Robin Rochester Jaques, who attained the rank of flight lieutenant with the RAF, was a keen sportsman and became a semi-professional footballer. He signed to Clapton Orient and Fulham F.C., but his career was cut short when he died in a flying accident on 8 August 1923. Upon his death, Mary, Jacques and her elder brother Robin moved from Newton in Lincolnshire to London, where Jacques was sent to the Lady Margaret primary school in Chelsea. In July 1930 Jacques started her secondary schooling at the Godolphin and Latymer School in Hammersmith, and also attended a local dance school, the Dean Sisters Academy, where she was a principal dancer in the Academy's shows. She left Godolphin and Latymer in the summer of 1939 with unremarkable grades. She continued intermittently with amateur theatricals, and in May 1939 appeared with the Curtain Club in Barnes in productions of "Fumed Oak" and "Borgia".