Elżbieta Zawacka had arrived in the UK in May following a perilous journey lasting several months across 1,000 miles of occupied territory.
Branded "the captain in a skirt" and "a militant female dictator" as she confronted those in charge in London, her efforts would transform the status of women in the Polish Home Army, helping to save thousands of lives.
On her return to her homeland, and having played a major role in the largest organised insurrection against Germany in World War Two, her "reward" was to be captured, tortured and jailed by her own government.
So who was the woman who went by the name of Zo, and what inspired her to acts of such defiance and bravery?
Elżbieta Zawacka was born in 1909 in the city of Toruń, a part of Poland which had been under the control of Prussia, then later Germany, for nearly a century.
At the end of World War One, the area was reclaimed by Poland. When both Germany and the Soviet Union invaded the country in September 1939, Zawacka joined the underground resistance, taking the code name Zo and building an intelligence network made up nearly entirely of women that covered the size of Wales.
Her blonde hair and perfect German made her an ideal candidate to act as its main courier, smuggling microfilms packed with military information hidden in objects such as toothpaste tins, keys and cigarette lighters - often into Berlin where the illicit cargo would be handed to another agent to be passed on to the West.
"It's really ironic," says Clare Mulley, historian and author of a new book, Agent Zo. "She has to bring information from Nazi-occupied Poland right into the heart of the Third Reich as that's the fastest way they can get it to London."