Friday 2 June 2023

Decoders of the WW2 Special Operations Executive

by Deborah Swift

After the fall of France and Belgium, a new organisation was formed – the Special Operations Executive (SOE) to strengthen subversion and sabotage in occupied territory and behind enemy lines.

To disrupt the enemy, agents sent abroad were charged with destroying railways, utilities such as telephone exchanges, bridges and factories, and then also to organise resistance cells of volunteers from within. Churchill’s famous instruction to Hugh Dalton, the then head of the SOE was to 'set Europe ablaze!'

The SOE headquarters, to train and recruit enemy agents, was in Baker Street in London, and the SOE began to recruit men and women to fill their ranks. One of the roles they needed to fill was that of decoders, women who would try to unscramble the ‘indecipherables’ – messages from agents abroad who had mangled their coding either through fear, pressure or simply forgetfulness.

These women had some skill in puzzle-solving, for example crosswords, but little else in the way of experience. Often they were daughters of someone else in the service, or of a friend or neighbour, as was all top secret and done by word of mouth. In my novel Nancy arrives there because her brother is already working for the SOE.

Women were recruited from all walks of life, the main criteria being that they had the language of the place they would be operating in, and were calm under pressure. The trainers tested them mercilessly, even going so far as to subject the women to enemy-like interrogations and they were rigorously vetted both during recruitment and during training.


Leo Marks in his book ‘Between Silk and Cyanide’ details all the methods that were tried to make the codes easier for agents to use. These included the use of poem codes (the agent and his decoder would learn a poem as their crib sheet) to printing on silk with disposable single-use grids of numbers.

The average lifespan of an agent sent abroad by the SOE was a mere six weeks, which means many were caught and killed earlier. In Holland the messages were broken very efficiently by the Germans, and after the first few Dutch agents were captured, it made it easier for German Intelligence to transmit as if they were the agent, getting the key to the code through torture and intimidation. The people at Baker Street were unaware they were decoding messages from the enemy who had infiltrated the resistance.

The agents that were still free were always looking over their shoulder. The slightest mistake, such as transmitting too often, would lead them to be discovered. This fact meant that decoding was a high pressure job. The women in Baker Street were working against the clock to crack the message – and the longer it took, the more likely the agent would send it again and that would put them at risk. Just to hop on the air waves was dangerous, when the German detector vehicles were scouring the area for illegal signals.

In my novel, Nancy goes on to work as an agent, to be the one sending rather than just receiving the radio messages. They were few restrictions on what agents could do, and outside the SOE the organisation became known as the ‘Ministry for Ungentlemanly Conduct’. This was because the SOE was responsible for high profile missions rather than the secretive low profile favoured by the Secret Intelligence Service, usually known as MI6.

For Nancy’s journey I researched the various countryside properties that were requisitioned by the SOE. Remote locations were used, such as the remote Arisaig in the Highlands of Scotland, so that the agents could develop skills in how to kill with their bare hands; the preparing of disguise, how to sabotage a train; and even how to break in and out of buildings by picking the lock with wire. Other country Houses that were used in SOE training included Winterfold House, Cranleigh, and Fulshaw Hall, Cheshire. The latter was the place where agents did parachute training. Several agents were injured during this training which included jumping out of a barrage balloon over a Manchester airfield.

If an agent survived weaponry training and passed the parachute test, they were ready to go behind enemy lines. The agents were assisted on their missions with some James Bond type equipment supplied by ex-film property makers working in an old hotel called The Thatched Barn – special clothing, cases to conceal radio and camera equipment, explosive devices. They also supplied false documents for the agents’ cover stories.

Sir Stewart Menzies head of the Secret Intelligence Service denigrated the SOE as 'amateur, dangerous, and bogus' and eventually the RAF, sick of losing planes to drop agents into Holland, simply refused to lend out their aircraft for these clandestine drops. They would rather drop bombs than agents. Nevertheless, the SOE produced many brave men and women whose actions were courageous, intelligent and awe-inspiring. I hope Nancy Callaghan, my main character helps you experience what life was like for those women who joined.

Read more about Female Spies of the SOE

See also Seven Stories from SOE agents

Find me at  or on Twitter @swiftstory

No comments: