As soon as German agents were recruited to the British double-cross
system they were quizzed about German espionage methods. In her
interview Nathalie Sergueiew recounted the story of her life, described
the appearance, character and relationships of her Abwehr
contacts, and explained the unique cipher she was taught, which
was based on the pages of a certain edition of a French novel. In
this extract Sergueiew describes the methods of secret ink writing
she learnt in Germany.