Between Silk and Cyanide (29 page)

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Authors: Leo Marks

Tags: #Biography & Autobiography, #Historical, #Modern, #20th Century, #Military, #World War II, #History

BOOK: Between Silk and Cyanide
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TWENTY-TWO
 
 
The Launching of Plan Giskes

Locked in my desk in readiness for this moment were brief notes on fctfae background and performance of every Dutch agent, and a detailed blueprint of Plan Giskes.

At arm's length with the plan at last, I reviewed the elements likeliest to determine its outcome:

  1. 1 Boni's record (no detail could be considered irrelevant)
  2. 2 The message to be sent to him
  3. 3 The concept itself.
 
Boni's Record
 

Boni (formerly known as Spinach; real name Cornelis Buizer) was dropped near Assen on 23 June 1942 with his organizer Parsnip. He had (transmitting regularly ever since and had become one of the busiest operators in Holland, handling not only Parsnip's traffic but that of Potato and other key members of the Parsnip/Cabbage organization.

A radio operator in peacetime, his 'touch' at the keyboard and knowledge of wireless procedures made him, in the words of a Grendon signalmaster, 'as good if not better than anyone here'. His coding was equally efficient and his security checks were invariably correct, though he had twice omitted them.

The volume of traffic which other agents entrusted to him allowed to straddle most of the bizarre events which had taken place in Holland in the past six months.

It was Boni who had been at the heart of the traffic snarl-up between London and Holland which lasted from 3 August to 12 November last year.

It was Boni who suggested that all Parsnip's traffic should be in his (Boni's) code. He subsequently made the same suggestion for all Potato's traffic. N section acceded to both requests, Ozanne refusing to intervene.

It was Boni who claimed that two key messages from London to Potato had been indecipherable. These messages had been checked and rechecked and had been perfectly encoded. Nor had there been any atmospheric problems which might have caused Morse mutilation to the indicator-groups. It was far likelier that the Germans had been unable to answer London's questions satisfactorily and had been playing for time.

 
The Cancelled Message
 

Message number 60 to Boni of 15 February was in reply to his number 58 of the 9th, in which he'd confirmed that a reception committee would be standing by for Broadbean and Golf. He'd also stated that he would run completely out of funds within the next two months and asked London to send money urgently. He'd added that he was recruiting new agents for the Parsnip/Cabbage organization.

The message which Bingham wanted to cancel promised Boni that 10,000 florins would be dispatched with Broadbean and Golf, and confirmed that the reception committee should stand by for a dropping operation on the 16th. It also confirmed the arrangement of the lights, and asked for details of the new recruits he was enlisting. It ended with a sentence in Dutch which I took to be a message to be broadcast over Radio Oranje or a password to be used in the field. This was an excellent message for the purpose of Plan Giskes. It was long (over 300 letters), had substance and, above all, called for a reply. The nature of that reply would determine whether Boni, and the agents for whom he operated, were in enemy hands.

The trap was basically so simple that its best chance of success lay in the Germans not believing that it could have been devised by simpletons.

 
The Concept
 

I intended to send Boni an indecipherable message which he could not possibly decode without the help of a cryptographer. But it would be no ordinary indecipherable. These can sometimes broken by luck. This indecipherable would be encoded in such a way that if Boni replied to it other than by stating that it was indecipherable then an expert must have helped him to unscramble it.

And that expert had to be German.

The incentives for the German to reply to it were very great indeed (and will be dealt with under 'possible German reactions'). But there was one imponderable factor which was more important than any of these. What if Boni were NOT in enemy hands?

However remote the possibility, it had to be catered for.

 
Special Precautions
 

If Boni were free but couldn't decode his instructions an entire operation could be jeopardized.

But if Boni couldn't decipher a message that he wasn't supposed to receive anyway because its contents were obsolete, no harm would have been done to him apart from the tedium of trying to decode it. That was why I'd delayed Plan Giskes until the Dutch cancelled a message to the field.

And if he made the mistake of replying to it, he'd tell us what we wanted to know.

 
Method of Encoding
 

The poem was:

 

I sometimes wish
I was a fish
A-swimming in the sea
A starling on a chimney pot
A blackbird on a tree
Or anyone but me.

 

I chose five words and numbered the letters sequentially, wishing I had the dexterity of the Grendon coders:

TREECHIMNEYF I SHWAS SEA 19. 15. 4. 5. 3. 9. 11. 13. 14. 6. 21. 8. 12. 16. 10. 20. 1. 17. 18. 7. 2.

I began by encoding the message in the normal way but deliberately misspelt several words of the text to give the impression it was the work of a tired and careless coder.

Then came the point of no return. I transposed two columns in the wrong order—a favourite pastime of Peter Churchill's (known in the trade as 'hatting').

The effect of 'hatting' was to throw the letters out of alignment so that some of the clear-text would read normally, and the rest (to the untrained eye) would be gibberish. A cryptographer could tell at a glance what had happened and would calculate how to 'unhat' the columns to bring the letters into proper alignment—a process which would tax his patience more than his mathematics. But agents like Peter Churchill also 'hatted' columns in the second transposition. A double dose of 'hatting' would be an altogether different matter. It would throw the letters much further out of alignment and make the cryptographer's task at least twice as onerous. This posed a (to me) unanswerable problem:

Swamped by important military traffic, how much time could the Germans devote to unravelling dropped stitches in an agent's message? What priority did they give to SOE's traffic?

These were the questions I'd wanted to ask Tiltman. Without his guidance, I took no chances on the Germans being overloaded and encoded the second transposition normally. It was essential that they didn't take long to unravel 'London's mistake', but possession of Boni's poem would cut the time by half, and after a few 'Gott in Himmels' they'd be certain to spot some key-words amongst the surrounding gibberish:

FLORINS would appear as FLOR with INS in the line beneath it.

THOUSAND would appear as THO with USA and ND in the same line.

MESSAGE (a word which all cryptographers looked for) would appear as MGE with ESSA in the line above it.

A few nudges later and the rest of the message would fall into place them.

 
Problem Areas
 

At this late stage the only one worth a final ponder was Giskes's reactions to an indecipherable from London.

He'd pretended that two of our messages to Potato were indecipherable. When confronted by a genuine one, why wouldn't he tell us that it was indecipherable instead of attempting to reply to it? Because he was playing for time with Potato. But time was against him now. With a dropping operation one night away—with agents, florins, containers, the lot, about to descend on him—why should he risk causing even a few hours' delay by asking London to repeat a message when he already knew its contents?

I was convinced that we had everything to gain and nothing to lose trying to catch Giskes in an off moment.

It was time to find out.

Hoping that Bingham wouldn't suddenly appear, I handed message 60 to the Signals Office supervisor, and told her that I'd encoded it myself to save time. I then instructed her to teleprint it to Grendon with top priority in time for Boni's next sked.

I hurried back to my office, my spine began tingling. Why did have a feeling in the mind of my back that somewhere in all this I'd made a mistake?

It wasn't until I received a panic-stricken call from the supervisor of Grendon night shift that I realized what was wrong.

The coders had discovered that the message to Boni was indecipherable. Knoowing that I'd encoded it, they hadn't checked it until it had been transmitted. I'd forgotten my standing instruction that all messages to the field must be double-checked and initialled by the supervisor.

I assured her that no harm had been done because message 60 had just been cancelled, and its replacement would be sent on Boni's next sked.

She asked if she should notify the Dutch section, which was the last thing I wanted, and I undertook to contact N section immediately and accept full responsibility.

An idea then occurred for turning the mistake to advantage, a prerequisite for survival in SOE. If I could tell the sceptics in SOE that a squad of coders had made a blanket attack on the indecipherable and failed to break it, they could hardly maintain (as some undoubtedly would) that Boni could have decoded it himself.

I informed the remorseful supervisor that I'd carefully checked my encoding and thought the mistake was in the teleprinting. To prevent this happening again I'd like the night squad to do their best to break it so that we could determine whose fault it was. I added that I was very anxious to know the result, and that if the girls hadn't broken it by the time I left the office I'd be grateful if she'd telephone me at home, no matter how late it was.

She promised that the night squad would start a blanket attack at once. I waited another hour, and then went home.

Boni stretched out a hand which had only one finger on it and screamed into my face, 'What have you done to me, what have you done to me?'

It was Mother trying to awaken me at six in the morning. She'd had a message from some girl whom she'd refused to put through to me. The message was to tell Mr Leo Marks that she and her friends couldn't do it.

Mother demanded to know what it was that she and her friends couldn't do that I had to be told about at six in the morning.

'Their duty,' I said.

Boni was still screaming when I tried to do justice to her black-market breakfast.

TWENTY-THREE
 
 
Special Devices
 

On the morning of 16 February there was a sound rarely heard in the code department—a sigh of relief—when a car called to take me to the Thatched Barn at Barnet. I'd forgotten that I was to spend the whole day with its commanding officer, Colonel Elder Wills.

Boni's next sked would be over by the time I returned.

The Thatched Barn was a famous inn on the Barnet bypass which Wills had skilfully converted into a camouflage and special devices station. The gifted colonel had offered me a conducted tour of his bizarre establishment not because he wanted to meet me but because he'd been offered a contra-account he couldn't resist: a conducted tour by Nick of an equally inaccessible workshop, the wireless station at Grendon.

It was my job to persuade him to give absolute priority to the camouflaging of WOKs.

I stood at a respectful distance as he proudly displayed a huge assortment of horse manure, camel dung, and mule, cow and elephant droppings, which had been delivered to him by the London Zoo at the personal request of Sir Charles Hambro.

It was a huge dollop of 'merde alors' for Wills that Hambro was not only a friend of Churchill's, and the youngest director yet appointed by the Bank of England, and a former chairman of Great Western Railways, but was also a fellow of the Royal Zoological Society and it was in this capacity that he'd persuaded the head of the zoo that his waste product could make a valuable contribution to the war effort.

I thought at first that this exotic collection of excreta was a present for C but he gleefully explained that it was in the process of being reproduced in plastic, and would then be hand-painted and filled with explosives. The horse manure was destined for Western and Northern Europe, the camel dung for North Africa, and the mule, cow and elephant droppings for the Far East. Once trodden on or driven over (hopefully by the enemy) the whole lot would go off with a series of explosions even more violent than the ones which had produced it.

Amongst Wills's more civilized creations were milk bottles which exploded when the caps were removed, fountain pens guaranteed to write off whoever unscrewed them, and loaves of bread it would be unwise to regard as the staff of life. He had a stock of cigarettes guaranteed to cure people of smoking as they were packed with incendiary and explosive materials, and they'd done no good at all to German stores, fuel tanks and armament dumps in France, Belgium, Holland and Norway. He also had on offer a variety of nuts and bolts which had been hollowed out and filled with explosives; these he warmly recommended for railway engines and shunting yards. Since agents often hid their WT sets in lavatory cisterns, he'd devised a lavatory chain which could act as an aerial. He also had a stock of lethal toilet paper which he hadn't yet issued because he couldn't be sure it would be used by the right behinds.

He took me into a shed which was packed with innocuous-looking suitcases specially made for carrying WT sets. Each suitcase had been artificially aged and designed to fit into the territory in which it would be used. Every suitcase was equipped with secret compartments and a false bottom.

Agents' clothing was the only problem which had come close to defeating him. He had to reproduce continental tailoring and stitching, which was very distinctive and varied greatly from territory to territory. He'd finally recruited a Jewish tailor, a refugee from Austria, who'd visited synagogues all round the country to borrow old clothes and labels from his fellow refugees. These labels were reproduced in Wills's workshop and sewn into the clothes, which the tailor had copied and which Wills had carefully aged. Boots and shoes (also carefully aged) were provided by a firm in Northampton, and Wills added sliding heels to them to provide cavities for microfilms and other small objects. In fact, everything in sight was 'suitably aged' but me.

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