Triple Cross (1966)
Triple Cross is a 1966 Anglo-French co-produced film directed by Terence Young and produced by Jacques-Paul Bertrand. It was based loosely on the real life story of Eddie Chapman, believed by the Nazis to be their top spy in Great Britain whilst in fact he was an MI5 double agent known as "Zigzag". The film was released in France in December 1966 as La Fantastique histoire vraie d'Eddie Chapman but elsewhere in Europe and the US in 1967 as Terence Young's Triple Cross. The title comes from Chapman's signature to mark he was freely transmitting by radio, a Morse code XXX.
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