by Leo Marks
Boni’s message (number 59) broke new ground. It contained an urgent request from Koos Vorrinck (code-named Victory). Vorrinck wanted the BBC to broadcast messages twice daily warning Dutchmen against a Gestapo agent named Johnny, who claimed to have arrived from London with important instructions from the Dutch government. The message ended with a short account of Mik’s (Cabbage’s) recruiting activities in The Hague and Leiden.
This was Boni’s first chance to report that he’d received an indecipherable from London, but it wasn’t necessarily significant that he hadn’t. He could easily have encoded his number 59 before receiving the message he couldn’t decipher. He must be given the benefit of such doubt as there was.
On the 17th Boni missed a sked. He’d missed remarkably few (eight in all) since he’d begun transmitting in June of last year, but missing this one wasn’t necessarily significant. Circumstances didn’t always permit WT operators to be at their sets when their signal plans demanded it, and their surest way of keeping their inflexible schedules was to be in enemy hands.
Yet it was now forty-eight hours since he’d received the indecipherable. He couldn’t know that it was a cancelled message any more than he could know what instructions it contained, and if he didn’t ask for it to be ‘checked and repeated’ at his next sked Plan Giskes would have to be disclosed to SOE at once.
He had a second sked on the 17th, and this one he kept.
London’s 62 was transmitted to him. It asked for a detailed description of Johnny (the Gestapo agent) and promised that Vorrinck’s request for warnings to be broadcast was being taken up immediately with the authorities concerned. The message ended with further questions about new recruits.
Boni acknowledged receipt of the message. He then transmitted ‘QR/U’, which signified that he had no traffic of his own to pass.
To me, this was the most significant message he had ever passed, but SOE didn’t respond well to negative inferences and I decided to wait for one more sked in case he referred to the indecipherable. Perhaps it was taking the Germans longer to break than I’d thought.
On the 18th Boni transmitted his sixtieth message. In it he confirmed that the first batch of containers had been successfully dropped, and that he was waiting for the rest, together with the agents and the 10,000 florins. He also confirmed that London’s messages had been received and understood and passed on to Victory and Cabbage, and that he would send further details about Johnny. He would also send information about the new recruits.
He didn’t once refer to the indecipherable, and there was even a phrase in the message which made me wonder if he were trying to tell us he was caught. It went all the way back to his days as a trainee operator.
Although it was appalling security, when Boni was at training school (spring ’42) all agents were instructed to use stock phrases like ‘Your message received and understood’. Boni had used this particular phrase only three times in the whole of his traffic. Was it coincidence that he was using it now? How could he (the most experienced operator in the field) say to London, ‘Your messages received and understood,’ when he’d had one for three days which was completely indecipherable?
I now realised that his missed sked was not insignificant. Nor were the gaps in his traffic. They were examples of Giskes’s timing. He’d waited until the first part of the stores operation was complete and the containers safely in his hands, before replying to London’s messages.
And with four more agents, six more containers and 10,000 florins yet to come, he had nothing to gain and invaluable time to lose if he asked the amateurs he was playing with to ‘check and repeat’ an indecipherable message they were clearly unaware of sending.
But his contempt for London (though justified) left me in no doubt whatever that Boni was caught.
And who else? What about Parsnip, Cabbage and Potato – and other agents whose traffic he handled?
What about Ebenezer and his gallant attempts to stip, step and stap?
What about the links these agents had with the Committee of Liberation? And the secret army? And Jambroes himself? How complete was Giskes’s victory? Surely to God not total?
Balanced minds must decide the next step.
‘Christ,’ exploded Heffer when I owned up to Plan Giskes. ‘Now you’ve done it.’
He accompanied me to Nick’s office and stood beside me while I tried to prove that Giskes was head of N section.
Nick listened to me with his eyes half-closed, then glanced despairingly at Heffer and examined the indecipherable like a coroner with a putrescent corpse. A few moments later he put it in his briefcase and rose abruptly from the desk.
Ignoring me completely, he hurried to the door, addressing Heffer over his shoulder. ‘See that he stays in his office. And stay there with him till I get back.’
The Guru and I had the office to ourselves.
He refused to discuss Boni’s traffic. His immediate concern was the harm I had done to the Signals directorate.
With a final puff of his cigarette, and probably of me, he said that Nick was about to be appointed head of Signals, that he’d spoken highly of me to CD and Gubbins and that my unauthorised actions would reflect on his judgement in the worst possible way. They might even result in Ozanne continuing in office, which would be the greatest disservice anyone could render SOE
I tried to assure him that I would take full responsibility but he shook his head. My conduct would still cast doubts on Nick’s judgement of people.
And on his. He had been my greatest supporter till now.
Stubbing out his cigarette as if it were an errant coding officer, he warned me that when Gubbins returned from North Africa (he’d been away since 21 January) my unauthorised action would be reported to him. He also warned me that if there were any other irregularities I ought to own up to, now was the time to do so. It would be fatal to let Gubbins discover them for himself. Did Heffer suspect what I’d been doing with de Gaulle’s secret code? I’d sometimes wondered.
Nick hurried back without saying where he’d been and proceeded to prove the Guru’s prescience. My report on Plan Giskes would be shown to Gubbins when he returned in March and the general would decide what action – if any – was called for. In the meantime, under no circumstances must I discuss Plan Giskes with N section or with anyone else in SOE. If the country sections found out that their traffic had been tampered with by someone in Signals, they’d lose confidence in the whole damn lot of us. Was this clear?
‘Yes, sir.’
It was even clearer that he and Heffer had lost it in me.
TWENTY-FIVE
Permission to Proceed?
By the end of February, SOE’s bid to convince the Chiefs of Staff and other sceptics of its D-Day potential had been launched with last-chance urgency.
The six Gunnersides had dropped into Norway; Passy and Tommy had landed in France; and for those who believed the collected works of Herr Giskes (otherwise known as the Dutch traffic) the Golf team had arrived safely in Holland and were staying with their reception committee. I was still waiting to hear when Tiltman’s assistant was arriving from Bletchley to discuss the production of WOKs, but I now had another reason for wanting to see him. I was determined to introduce one-time pads for agents’ traffic but couldn’t do so without Bletchley’s help.
Although Tiltman had pronounced WOKs ‘an excellent system as the keys could be destroyed after every message’, they had two drawbacks. They obliged agents in the field to use double-transposition, a cumbersome process in any conditions, and for security reasons every WOK message had to contain at least a hundred letters, which was often far more than the agents needed to send.
But one-time pads were unbreakable even by Bletchley, and if they were issued to agents their traffic would have a diplomatic level of security, which was what it deserved. They could send as few as ten letters and get off the air, and I wanted them to keep their WOKs in reserve and have poems in their heads in case they lost their silks o
r couldn’t get to them in time.
But there was one obstacle in this cipher Utopia, and I was counting on the Bletchley expert to help me surmount it. In its present form, onetime-pad traffic was passed entirely in figures, which would increase the dangers of clandestine communication.
The one-time pad (which had been invented by the Germans in the First World War and adopted by all those with anything worth hiding) required the use of a code book with figures printed opposite every phrase.
The coder looked up the requisite phrases, copied out the figures beside them and wrote them underneath the figures of a one-time pad. The two groups were then added together without carrying the tens:
one-time pad:
8209
code book:
0796
8995
The figure 8995 would be followed by the rest of the message, which would remain unbreakable for as many years.
But it would be a very different matter if agents tried to use the same procedure. Figures took longer to transmit than letters and would lengthen their skeds (every figure consisted of five dots or dashes instead of the one dot or dash to a maximum of four dots or dashes which letters required). Figure traffic would also increase the likelihood of mistakes in transmission and (most serious of all) would stand out from the rest of the clandestine traffic in the occupied territories.
There must be a way of adapting the principle by substituting letters for figures and abandoning the code books. But what was it?
I decided I had nothing to lose but sanity by trying to find out.
Seventy-two hours later I was no closer to the solution.
A batch of telegrams from Stockholm in main-line cipher made the long nights bearable.
On 16 February the six Gunnersides marched across the Hardanger mountains and on 23 February linked up with the four starving frostbitten Grouse (now code-named Swallow).
They decided to attack the heavy-water plant wearing British battledress so that in the event of capture they had the right under the Geneva Conventions to be treated as soldiers. Each man agreed to take his L-tablet if capture seemed inevitable.
Carrying heavy explosives, they reached Rjukan, which was heavily patrolled by SS reinforcements, and at thirty minutes past midnight launched their attack. Less than an hour later the plant was virtually demolished.* Even more incredibly, the ten agents suffered no casualties.
Poulson, Helberg, Strømsheim, Storhaus and Idland made their way to the frontier and crossed into Sweden, still wearing British battledress. Knut Haugland, Haukelid and Kjelstrup stayed in Hardanger to monitor the damage and were joined there by Einar Skinnarland.
His file of indecipherables was just about ready for its second volume, and he more than anyone would benefit from a simple system such as a one-time pad consisting entirely of letters.
If only for his sake, I tried once again to find the formula. Five thousand attempts later I was still looking for it.
Note
* It took the Germans six months to restore the plant to even partial capacity.
TWENTY-SIX
Court Martial
By the beginning of March, SOE was still operating without an official directive, and every department seemed to be holding its breath in case it was its last. While C pushed ahead in all directions, we were dress-rehearsing for a show which couldn’t find backers.
I was luckier than most because I had one pleasurable experience. I was given the opportunity to service the Danes, if providing them with poem-codes could be considered a service.
I was asked by Hollingsworth to brief nine agents, including the new head of the Danish Resistance.
The Danish traffic made clear (and Stockholm’s messages confirmed) that a new organisation had been formed in Denmark. Its code name was Table, and Mogens Hammer (the present head of Danish Resistance) was now called Table Top and his chief of Communications (Duus Hansen) was now Table Napkin. Hammer was unaware that he was about to be replaced by Flemming Muus, who would be known as Table Talk.
In the first week of March I gave a final code briefing to Muus, Table Salt, Pepper, Mustard and five other condiments.
The new head of Danish Resistance was a large and exceedingly jovial zealot with the knowing eyes and infectious self-confidence of a stand-up comedian booked to play Hamlet in his home town. He and his supporting cast of eight were to be dropped into Denmark on 12 March.
I also inflicted poem-codes on three Dutch agents – Pieter Dourlein, Peter Arendse and Peter Bogaart, who were code-named Sprout, Seakale and Kohlrabi respectively. The three Peters were dropped into Holland on 9 March. I regarded their chances of survival as nil as Boni had arranged their reception committee.
On 10 March Heffer warned me that Gubbins was back in his office, and that to help him evaluate the results of Plan Giskes Nick had given him the report on the absence of Dutch indecipherables which I’d written in January. He added that Gubbins would be far too busy to see me in the day and that I must stand by for a late call during the next few nights.
Realising that my stay in SOE might soon be coming to an end, I renewed my attempts to devise a letter one-time pad but with no more success than before, and it was a relief when I received a phone call from Nick well after midnight instructing me to report to the general’s office at once.
Six months ago a novice night duty officer and an armed lance corporal, who was supposed to be his escort, had patrolled the whole of Michael House searching for scraps of paper, enemy agents and each other.
Was it really only six months since that evening of havoc when I’d knocked on the general’s door to enquire if I should inspect his credentials?
His terse ‘Come!’ hadn’t changed.
Nick was seated to his left and avoided looking at me, but the general’s scrutiny more than made up for it.
Pointing to a chair Gubbins then immersed himself in my Dutch report, and within a minute had reached the third of its closely packed pages. Colin Gubbins was a closely packed man.
Described by Tommy as ‘a real Highland toughie, bloody brilliant, should be the next CD’, he was short enough to make me feel average, with a moustache which was as clipped as his delivery and eyes which didn’t mirror his soul or any other such trivia. The general’s eyes reflected the crossed swords on his shoulders, warning all comers not to cross them with him. It was a shock to realise that they were focused on me.
‘What’s this word?’ he demanded, pointing at a scribbled annotation.
‘ “Bollocks”, sir.’ It was a reference to Boni’s claim that London had sent indecipherables to Potato.
He turned the page in silence.
At his rate of reading he’d soon reach another annotation – ‘Is this bit too technical for some of the pricks who may have to read it?’
From the sudden anger on his face I thought that he might already have reached it. He turned sharply to Nick. ‘This breakdown of communication between Signals and N section when, according to Marks, the wrong codes were used – I want to know who was responsible. A full report.’
Nick nodded eagerly as if glad to be of use.
The Mighty Atom resumed his reading but stopped suddenly in the middle of a page and glanced at Nick. Nothing was said, but Nick gave the slightest of nods, as if he understood what was worrying the general. It was the kind of look I’d seen my parents exchange.
The general levelled it at me. ‘This report – how many copies did you make?’
‘One, sir. Colonel Nicholls has it.’
‘How many people have read it? The complete list.’
‘Colonel Nicholls and Captain Heffer, sir.’
‘The Dutch know nothing about it?’
‘No, sir. They think the message was cancelled.’
‘Who typed this report?’
‘I did, sir. Sorry about the mistakes.’
‘Your secretary hasn’t seen it?’
‘No, sir. She wasn’t with me at the time.’
; There was a warning gleam in those forbidding eyes. ‘What did you tell Colonel Tiltman about the Dutch situation?’
‘Nothing, sir. I was instructed not to discuss the country sections.’
‘And you always obey your instructions?’
‘No, sir. But in this instance I did.’
There was silence as Celt met Jew on the frontier of instinct. We then went our separate ways.
A minute later he reached the last page and reread the closing paragraph, which was probably a reflection on my style of writing. It had been hard to find the right finish at four in the morning:
… yet despite the pressure under which they’ve been working, despite deaths by drowning, by exploding minefields and by dropping accidents, despite every kind of difficulty, danger, setback and frustration, not a single Dutch agent has been so overwrought that he’s made a mistake in his coding… It seems to me unarguable that the bulk of their messages have been sent by the Germans and the main question is no longer which agents are caught but which are free.
The general closed the report and, without pausing for breath, proved that he was a field-marshaller of facts: ‘According to you, twenty per cent of all indecipherables are caused by Morse mutilation to the indicator groups, and seventy per cent by mistakes in the agents’ coding. Of these mistakes, twenty-five per cent are caused by wrongly encoded indicator groups.’
An excellent example of total recall, but what was his point?
‘Now then – the Dutch traffic. According to you, the only indecipherables received from Holland were due to Morse-mutilated indicator groups – but you don’t explain how you people distinguish between an indicator group that’s been Morse-mutilated, one that’s been mistransmitted and one that’s been misencoded. Explain now.’
