Mata Hari was a Dutch housewife and mother who became an exotic dancer in Paris.
Legend has it she slept her way across Europe during the Great War, gathering intelligence for the Germans.
She is also said to have faced her firing squad wearing nothing but a fur coat - which she flashed at the last minute to try and put the soldiers off their aim. But was she really the spy she was made out to be?
Government papers show she was arrested and interrogated three times by MI5, but released each time because there wasn't enough evidence against her.
Julie Wheelwright is Mata Hari's biographer and she told Philippa Dolley what surprised her about the revelations ...
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