Another, "I'm not a monster" fan here.
I watched a fascinating thing on YouTube about 'agent Garbo'.
A Spanish couple in WWII volunteered to spy for Britain, they were told 'no' so they set up a domestic spy ring to be double agents.
They moved to Portugal and contacted the Germans, saying they were in Britain and pro Nazi.
The husband (Juan Pujol García) used train time tables, British newspapers and radio to create fictitious 'intelligence', he told the Germans he had a contact who was flight crew flying between London and Lisbon to account for the Portuguese post mark / stamps.
The British took notice when the German's tried to find a fleet of ships Garbo had made up.
So he became a double agent and moved to Britain, he also 'ran' about 30 other agents, all fictitious.
He even had an agent become ill, die, have an obituary in the paper and then a pension paid to the non existent widow.