When Vermehren returned to Berlin on leave, the couple agreed they would defect to Britain. So that Elisabeth could travel to Istanbul, she procured an official assignment from the Foreign Office in connection with the Archbishop's visit to Turkey. They travelled by train to Istanbul, but at the border crossing into Bulgaria, Elisabeth was arrested by Gestapo agents and taken to the German embassy in Sofia, though Vermehren was permitted to continue to Istanbul. In Sofia, the ambassador was a family friend who (in cooperation with the Abwehr station chief) sneaked her on board a diplomatic courier plane to Istanbul. Meanwhile, Erich had made overtures to the British Secret Intelligence Service, which already had a file on him, through its counter-espionage representative Nicholas Elliott.