In May 1940 she returned to England and in February 1941 she joined the French section of the Special Operations Executive (SOE). Although she remained a civilian and had no military rank she was officially the section's intelligence officer while serving as assistant to section head Maurice Buckmaster.
When the allied victory in Europe was accomplished, she was commissioned as squadron leader in the Women's Auxiliary Air Force (WAAF), and went to Germany. Her self-appointed mission was to investigate the fate of the 118 F section agents who had disappeared in enemy territory. She succeeded in every case except one.