Between Silk and Cyanide (17 page)

Heffer blinked, which was his way of holding up his hand, and asked what my conclusions were.

I put to him that indecipherables were a black plague and that there was only one feasible explanation for the Dutch agents' immunity from it. They were operating under duress.

He warned me that I was basing my conclusions on a negative inference. The Dutch section and others were likely to say that the 'discovery' was no more than coincidence or a specialist juggling with statistics. He advised me to look into it more deeply and prepare a written report for Nicholls, who'd be back in a week's time. I knew then that he took it as seriously as I did.

Showing signs of duress himself, he stressed the importance of finding supporting evidence that the agents had been caught. Inspired guesses only produced inspired excuses. He warned me against saying anything to the Dutch section prematurely. They might send a message to the field asking
why
there'd been no indecipherables.

He expressed, if the term were applicable to his tempo, interest in knowing what had pointed me in this direction.

I didn't tell him that it was a combination of Group Captain Venner and Air Commodore Freud.

The first thing to establish was who was actually encoding the messages. Was it the agents under supervision? Or were the Germans doing it themselves? The only way to determine this was to study the coding habits of every Dutch agent.

I took the clear-texts of all the messages which had been received from Holland since June '42 and encoded them as the agents had. It was a long and exhausting process and I found that by the end of it I'd made many mistakes, and that two of my messages were completely indecipherable. According to Freud, this was likely to be deliberate.

A pattern emerged which was not quite distinctive enough to be called a style. It was based upon a freedom of choice. Every agent could pick any five words of his poem for his transposition keys. Agents tended to have favourite words and often used the same combination for a number of messages. These words either had an emotive value for them or they were the easiest to spell. But above all, agents favoured the shortest words they could find because they minimized the tortuous process of numbering the key-phrases.

The Dutch agents were perfectly normal in their ratio of favourite words to new ones. I noticed that Boni never chose a key-phrase without the word 'wish' in it. They were also normal in their choice for the shortest words—with one exception: Ebenezer regularly used at least two of the longest words at his disposal. For one message he'd even used three, making his transposition-key over twenty letters long. Done by Haugland, it was an example of a first-class coder. Done by Ebenezer, it could mean that he had plenty of time for his coding and showed a marked departure from an agent's norm. The question was, was it the norm for Ebenezer?

I contacted his training school to check the length of the key-phrases he'd used in his student days, but his training messages had long since been destroyed. The instructor reminded me that it wasn't until July that London had ordered the training schools to retain every agent's practice messages. I was familiar with this instruction. I'd sent myself in the name of Ozanne.

It didn't help with Ebenezer but I was now able to examine the coding exercises of every Dutch agent who'd been sent into the field since July '42. They'd been average to good coders and each of them had sent a trainee's normal quota of indecipherables. Yet not one Dutch agent had repeated his early training mistakes when he reached field.

This put the Dutch in a class apart.

So did their wireless habits.

Reports from the Grendon signalmasters showed that the Dutch WT operators made as many procedural errors as other agents and that their traffic was as prone to Morse mutilation.
But with the exception of Boni, not a single Dutch WT operator had asked the Home Station to repeat a message on the grounds that it had been garbled in transmission and couldn't be deciphered.
This was an important discovery but it had to be kept in perspective.

Grendon's transmitters were powerful and the operators highly trained and the incidence of agents asking for repeats of messages was small. But it had happened several times in every country section except the Dutch.

The agent who'd come closest to it was Ebenezer. In April '42 he'd suddenly terminated a sked because of interference. Even so, he had never asked for London's messages to be repeated.

Why was it, then, that this same interference, which so troubled other countries' agents, hadn't caused the Dutch to send or receive a single indecipherable, with the possible exceptions of Parsnip and Potato? I broke off at this stage to summarize for Nicholls my findings to date. I reported that, on balance, I thought that the Dutch agents were doing their own coding and that their messages were being checked by the Germans before transmission. I couldn't yet specify how many agents had been caught or who they were, but at least a large question mark had to be put against the names of Abor, Ebenezer, Boni, Trumpet and Potato.

The next phase would determine whether I could produce any substantive proof. It would be the first time that I had studied a country section's traffic for its content alone.

I read through every message which the Dutch section had sent to the field and compared each one with the agent's replies. It needed a trained Intelligence officer to do this job properly. The traffic contained so many disturbing implications that halfway through a second reading I went back to the beginning to make a précis of the principal exchanges. It was like trying to synopsize the Domesday Book.

When the précis was finished I listed the dropping operations in chronological order with the names of the agents involved. Remembering that Nicholls was a professional soldier, I refrained from adding a layman's comments. That was the most difficult part.

Ebenezer and Thijs Taconis (referred to in messages as 'Tall Thijs') were dropped into Holland in November '41. Their early traffic was mainly concerned with bread-and-butter Intelligence and the problems of setting up communications. Ebenezer's first message was received on 3 January and his skeds, which he kept regularly, were on alternate Fridays.

On 28 February two more agents Jordaan (Trumpet) and Ras (Lettuce) were dropped near Holten. Trumpet was referred to in messages by his field-name, Jeffers.

On 15 March the Dutch section instructed Ebenezer to find a dropping ground for a new agent and a number of containers. The operation was code-named Watercress and would take place in the next moon period. Ebenezer replied that he was looking for a dropping ground and would prepare a reception committee.

On 17 March London informed Ebenezer that Taconis had found a dropping ground near the banks of the Reitdeip canal. Ebenezer was instructed to prepare it for Watercress. Ebenezer replied that the Reitdeip dropping ground was too isolated and suggested that the drop should take place on the moorlands near Steenwijk.

It was in this message that he began his peculiar spelling of 'stop' 'stip', 'step' and 'stap', and omitting his secondary security check.

On 25 March the Dutch section agreed to accept Steenwijk and informed Ebenezer that Abor would be dropped there within forty-eight hours. He was instructed to arrange the ground lights in the form of a triangle; the reception committee should identify itself to Abor by using the name Ebenezer.

On 28 March Ebenezer reported that Abor had been dropped safely with four containers.

On 29 March Lieutenant Andringa (referred to in messages as Akkie) and Jan Molenaar (Turnip, field-name Martens) were dropped Holten.

Also on 29 March Ebenezer was instructed to find out what had happened to two agents who'd been dropped on 10 March and had failed to contact London.

On 4 April Ebenezer replied that one of the agents had been killed on landing and he was trying to establish contact with the other.

On 5 April Kloos (Leek) and Sebes (Heck) were dropped into Holland. They arrival coincided with a series of messages from the Dutch section of Ebenezer asking him to find out what had happened to Akkie and Martens, who had been out of touch with London since their arrival. Ebenezer reported that he'd had no success in tracing them.

On 9 April Trumpet informed London that he had just met Akkie at a safe-house in Haarlem. Akkie wanted London to know that his WT operator Martens (Turnip) had been killed on landing. Akkie still had Turnip's signal-plan and he wanted Trumpet to use it and be his WT operator until London could send a replacement.

The Dutch section at once agreed that Trumpet should handle Akkie's traffic and promised to send a new WT operator during the next moon period.

Lieutenant de Haas (Potato, field-name Pijl) was landed by motor torpedo boat on the Dutch coast on 19 April. He was the first Dutch agent to be equipped with a Eureka. He was to link up with Akkie. His messages were to be passed by Ebenezer.

On 24 April Trumpet sent London an urgent message over 300 letters long. It was so disturbing that I put an asterisk against it and against the messages it gave rise to, and then erased them. It was better for Nicholls to insert his own.

Trumpet informed the Dutch section that Leek and Heck could not communicate with London as their WT sets had been lost on landing. They had contacted the Lettuce group to ask for WT facilities. (Trumpet was Lettuce's WT operator.)

Trumpet went on to say that Pijl (Potato) had also been in touch with him. Fiji had been unable to communicate with London because he couldn't contact either Thijs (Taconis) or Ebenezer, who were to send his messages for him. Trumpet had agreed to pass Fiji's traffic until Thijs or Ebenezer could be reached.

The Dutch section at once sent a message to Thijs via Ebenezer informing him that Fiji had been trying to contact him. Thijs was told to make arrangements through the safe-house at Haarlem to meet Pijl. Taconis replied via Ebenezer that he would contact Pijl immediately.

This was the start of independent circuits of agents being put in direct touch with each other, all of them dependent on Ebenezer, Boni or Trumpet for their traffic.

On 20 April Trumpet informed London that Akkie had found a reliable local WT operator. Trumpet wanted London's authority to recruit him and teach him SOE's WT procedures. The Dutch section agreed to this request but stipulated that the new operator must send a test signal to London.

On 30 April the Dutch section informed Trumpet that the new operator's test signal was satisfactory but that he'd omitted his security checks. Trumpet was given specific details of these checks in the same message.

I put six asterisks against this one, then erased five of them.

On 2 May the Dutch section instructed Ebenezer to prepare a dropping ground on the Steenwijk moors for a large number of containers. Ebenezer confirmed that the dropping ground was ready. The drop took place without enemy interference.

On 11 May the Dutch section sent Pijl a message via Ebenezer's set instructing him to find suitable points along the coast where agents and equipment could be landed at night. He was to use his 'special equipment' for the first time.

This 'special equipment' was a lamp which emitted an invisible infra-red beam which signalled its position to a receiver on board a ship. The landing party would thus be able to pinpoint the spot where Pijl and his reception committee were waiting.

Piji replied via Ebenezer suggesting several suitable landing points on the coast and the Dutch section selected Katwijk.

On 17 May Pijl sent a message that he and a reception committee had waited at Katwijk all night but that the ship had not appeared.

On 19 May London informed Pijl that the operation was to be repeated in two nights' time.

On 22 May Pijl reported that shortly after midnight there had been gunfire at sea and that he had again waited several hours but had still not made contact with the ship.

On 25 May the Dutch section informed Pijl that the operation had been abandoned for the time being. Pijl was now to concentrate on helping Ebenezer's group. He was also to investigate the possibilities of sabotaging German ships in Dutch harbours.

All this traffic was passed on Ebenezer's set.

On 28 May Ebenezer was warned by London to prepare for the arrival of Beetroot and Swede.

On 29 May Beetroot (Parlevliet) and Swede (van Steen) were dropped to a reception committee on the Steenwijk moors. They were equipped with Eurekas and S-phones. The latter enabled agents to have ground-to-aircraft conversations. Beetroot and Swede were to mount an attack on the Juliana canal locks.

On 12 June Trumpet was instructed by London to prepare dropping grounds for the arrival of Parsnip and Spinach.

On 22 June Parsnip and Spinach parachuted to the Assen dropping grounds suggested by Trumpet. Parsnip was to link up with Potato, who was well known to Ebenezer. Parsnip and Spinach were to organize a sabotage group in Overijssel.

On 23 June Ebenezer and Trumpet were alerted to the imminent arrival of Marrow, the most important mission of all. Marrow was Professor Louis Jambroes. He was to be accompanied by a WT operator, Joseph Bukkens.

On 26 June Jambroes and Bukkens were dropped to Ebenezer's reception committee at Apeldoorn with the help of a Eureka. Bukkens was equipped with the prototype of a small, highly selective WT transmitter, the first of its kind to be issued.

The Dutch section was so concerned for Marrow's safety that it had suggested five different dropping grounds to Ebenezer before finally agreeing to Apeldoorn.

Ebenezer and Trumpet were amongst the many agents who knew why this mission was so important to the liberation of Holland. Jambroes was the official representative of the Dutch government-in-exile and a member of the National Resistance Council in London.

He was to take command of the Dutch secret army and prepare it for 'Plan Holland'—the code-name for the Chiefs of Staff's invasion plan to liberate the Low Countries. Jambroes was also to meet the leaders of the various Dutch Resistance groups and co-ordinate them under a National Committee of Resistance. His mission had the full support of the Allied High Command.