From "Between Silk and Cyanide - The Story of SOE's Code War" by Leo Marks, HarperCollins Publishers, 1998:


Maurice Buckmaster was the first country section head to be shown a WOK (worked-out key). Normally, responsive to everything which would enhance the welfare of his agents, he was facing the collapse of his two principal circuits, and suggesting new codes to him was like taking a drowning man's hand and offering to manicure it.

He gave a cursory glance at the WOK which I put in front of him, muttered that he didn't want his agents to carry another damn thing, and left the rest to Captain Noble, his signals officer.

He couldn't have submitted the code to a better qualified judge. Noble (real name Georges Bégué) was a self-effacing Frenchman with the added distinction of being the first SOE agent to parachute into the field. He'd been dropped blind into France in May `41, taking with him a rudimentary wireless set and a poem-code. He transmitted more than forty vital messages but had such contempt for is security checks that he'd ignored them altogether, and relied on pre-arranged questions and answers. He'd been arrested by the Vichy police in October `41, and F section didn't expect to hear from him again. But in July `42, he'd escaped from a Vichy-run prison in the heart of the Dordogne, taking nine of his fellow-agents with him. He made his way to Lyons, crossed the frontier into Spain, and was taken on to Buckmaster's HQ staff as soon as he returned to London.

He'd be a major asset to the Signals directorate as a briefing officer. But at this moment he could also be an insuperable obstacle.

I explained the advantages of silk codes to him but didn't mention their security checks. I wanted to see if he'd refer to them himself, and with a cynical little smile he eventually did.

Although he grasped the principle at once, I gave him a detailed exposition in case Maurice was tuning in. Noble waited impatiently till I'd finished, then copied out a pair of WOK-keys, rapidly encoded a message, and changed the indicator by secret numbers known only to him. As if to prove Nick's maxim, `once an agent always an agent', he checked his handiwork carefully while his fingers drummed out the code-groups in Morse. Satisfied that he hadn't forgotten how to doubly-transpose, he produced a razor blade and without asking permission (which I'd gladly have given) cut the keys off the silk and watched them smoulder. I knew just how they felt.

He then turned to Buckmaster, who was somewhere in France. `If I'd been given such a silk to take in,' he said, `I'd have troubled to use my security checks.'

Maurice relunctantly conceded that WOKs might be suitable for WT operators because they could hide them with their sets, but he was damned if he'd force organizers to carry codes as they moved around France, no matter how well the bloody things were camouflaged. He glared at me with his `My decision is final' expression.

Noble was silent when I needed him most.

I confided to Maurice that WOKs were in very short supply and that it was most unlikely that we'd be able to spare them for all his organizers as the Free French demands were likely to be heavy.

At this point I had my first order.

An outraged Maurice accused me of not realizing how important his organizers were, and he absolutely insisted that all F section agents were given silk codes or I'd damn soon hear from him. And so would Nicholls.

And if the WOKs weren't forthcoming he'd go straight to Gubbins.

Noble winked at me as I left.


The idea of BBC announcers reading short en clair messages to agents in the field had been conceived in 1941 by Georges Bégué, the first SOE agent to be parachuted into France.

Bégué (who'd escaped from a Vichy prison in `42 and was now Captain Noble of F section) had been given a poem-code and an elementary WT set, and dropped into the Châteauroux area to communicate with London. He'd soon discovered that the Germans were jamming his traffic, that their direction-finding vans were scouring the vicinity, and that he was risking his life every time he came on the air. He'd also realized that many of London's messages consisted of instructions to carry out orders he'd already been given. Anxious not to use his if he could possibly avoid it, he'd suggested to London that their last-minute instructions to him could safely be conveyed in short prearranged phrases, whose meaning only he and F section would know. If London agreed, he would listen every night to the BBC's foreign service until these phrases were broadcast.

His concept of `personal messages' was at once adopted, and rapidly spread to every country section in SOE. Since then, short plain-language messages had become an integral part of agents' communications, and were currently being used to confirm safe-houses, passwords and dropping operations, substantially reducing an operator's air-time.

They also fulfilled a function which Noble hadn't foreseen. They enabled agents in the field to say to those whose help they badly needed but who doubted their bona fides, `Make up a short message - it doesn't matter what - and I'll arrange for it to be broadcast a week from now on the BBC's foreign service.' The results of this offer never failed to produce the desired effects, and often enabled agents to borrow large sums of money on the lender's assumption (not always well founded) that London would repay the advance when the war was over.