Between Silk and Cyanide: The Story of SOE’s Code War – Leo Marks

Leo Marks first wrote his book about his time during the Second World War in the Special Operations Executive, Between Silk and Cyanide, in the 1980s but it failed to receive official clearance. It was not published until 1998. Why it was embargoed is not clear, but what is very evident is that Between Silk and Cyanide is less than complimentary about the workings of the SOE.

Marks originally applied to join the Government Code and Cypher School at Bletchley Park but failed to be taken on after the eight-week introductory course. Marks, though, did have a gift for codes and he was soon snapped up by SOE to help organise its communications with its agents.

His objective was to make the communications secure with the adoption of unbreakable or virtually unbreakable, codes. As soon as he joined SOE Marks exposed the amateurish weakness of the existing codes. After much persuasion he managed to convince his superiors that other methods should be adopted, which included the use of “letter one-tine pads”. These were printed on “silks”. If all went wrong and an agent in the field was captured by the enemy, an alternative to imprisonment and torture was to chew on the cyanide pill they were issued with; hence the title of the book.

One of the most infamous events in the SOE story was the turning by the Germans of the captured agents’ radios in Holland. The Germans played their “England Game” – Englandspiel – so successfully that virtually the entire SOE organisation in Holland was controlled by the Germans, resulting in the capture and death of around fifty agents. Another was the collapse of the largest network in France, the “Prosper” circuit. Again, this led to scores of agents and sub-agents falling into the hands of the enemy. Marks discusses both of these at length in his book.

The disaster that befell the Prosper circuit began when the agent Archambault, aka Gilbert Norman, sent a message to London in which he omitted to include his special double security check. This was put in place just in case a radio operator was captured by the Germans and forced to send and receive messages under German control. If the security check was omitted, it would indicate that he or she was no longer free and the messages would be treated accordingly in London. For almost eight months Norman had transmitted messages successfully with all the security checks given correctly. Then, on 27 June 1943, he sent the message which did not include his security check. This naturally caused concern at SOE headquarters in Baker Street. Marks quickly looked back through all of Norman’s previous messages to see if he had ever done this before. In fact the transmission had not been made by Norman but by a German using Norman’s radio.

Whilst Marks was investigating this, and without referring to Marks, Maurice Buckmaster, the head of SOE’s French Section, took it upon himself to reply personally. He informed Norman that he had forgotten to insert his check and accused him of committing “a serious breach of security which must not, repeat must not be allowed to happen again”.

It was strict policy never to refer to codes or checks in any message and when Marks learnt of what had happened he confronted Buckmaster who admitted that he had made a “terrible gaff”. Both Buckmaster and Marks now considered the possibility that Norman had been “turned”. Buckmaster, though, decided to keep sending messages to Norman as he believed that this would make him useful to the Germans and thus prevent him from being executed. This “gaff” so disillusioned Norman that he actually began to co-operate with his captors. Most of the Prosper circuit quickly fell into German hands.

Between Silk and Cyanide provides us with an insight into the workings of SOE headquarters from someone who was not ashamed to highlight the organisation’s failings, failings that in some cases cost the lives of some very courageous individuals.

Review courtesy of Britain At War Magazine.

Leave a Reply

Your email address will not be published. Required fields are marked *