by Leo Marks
They knew that in 1941 the Germans had ordered the plant to step up production of heavy water to 10,000 pounds within the next year; they knew how the Germans were planning to transport the heavy water from Norway to Germany; they knew the structure of the plant and its fortifications better than the layout of their own offices; they even knew where the guards were billeted, how many were on duty at any one time and the disposition of the sentries on the suspension bridge between Vermok and Rjukan. All this information had been passed by SOE to the Chiefs of Staff, who put it before Churchill.
The PM immediately asked Professor Lindemann, his chief scientific adviser, for a technical assessment. Professor Lindemann had no doubt at all (he seldom had) that the Germans required this heavy water to produce atomic bombs, atomic rockets and other atomic weapons as yet unknown.
The whole of SOE’s information about heavy water flowed from one source: Einar Skinnarland. He was an engineer at the heavy-water plant. He had helped the Norwegians to build it and he was now committed to its destruction.
Sorry Mr Skinnarland, sir. Code with both eyes closed, if you aren’t already.
The last document – in many ways the most revealing of all – summarised the history of the plant and the extraordinary way in which Skinnarland had been recruited.
The plant and its laboratories had been built before the war on the most isolated spot which the Norwegians could find – the Barren Mountain between Vermok and Rjukan, in the precipice- and glacier-bound wilderness of Hardanger Vidda. The Germans invaded Norway in 1940 and at once took over the plant – forcing its Norwegian technicians (including Skinnarland) to continue working there under supervision.
To find out more about the plant and if possible to recruit some of the technicians, SOE dropped Odd Starheim on to a snow-covered field in Norway in December 1941 and left him to find his own way to the Barren Mountain. It was the same Odd Starheim (code name Cheese) whose previous messages had helped the navy to sink the Bismarck and cripple the Prinz Eugen.
In March 1942 Starheim was introduced to Mr Skinnarland by a mutual friend – and it was sabotage at first sight. Skinnarland agreed to come to London with Starheim, bringing all the information he could about the plant and its fortifications.
Since SOE couldn’t provide the transport, Starheim hijacked a coastal steamer, ordering the captain at pistol-point to change course for Aberdeen. Starheim had also invited a number of other Norwegians to join him on the ‘trip’ so that they could be trained by SOE as saboteurs and WT operators. Tomstad sent a message alerting Wilson that Starheim’s boat was heading for Scotland and would welcome air cover. The RAF, as ever, obliged.
So did Skinnarland. As soon as he arrived in London he gave Wilson the fullest possible briefing about the plant – and in return was given a twelve-day crash course in the craft of sabotage and the agony of coding. In March ’42 he was dropped back into Norway – his first ever jump – and landed on ice near his home in Hardanger Vidda. He reported to the plant, explained that he’d been ill and resumed his job as if he’d never left it. He was now awaiting the arrival of a sabotage team from London.
The four agents who’d been selected to blow up the plant had been waiting since mid-April to be dropped into Norway. The operation had already been postponed three times due to exceptionally bad weather, and they were still in London expecting the next attempt to be made in late September. The code name of the operation was Grouse.
I closed the Grouse files.
Was it coincidence that in three days’ time I had an appointment to brief four Norwegian agents who ‘were standing by to go into the field after one or two delays’? Wilson had arranged this appointment personally (unusual) and confirmed it to me in writing (unprecedented). They had to be the Grouse team.
And when they made their bid to deny the Germans the use of atomic power they would be sending their messages in the poem-code.
I telephoned Ozanne’s secretary and said that I needed to see the colonel on an urgent matter, that it would take about an hour and that I would be grateful if Colonel Pollock could be present. I also requested the use of a blackboard.
She asked me to hold on and a few moments later told me that Colonel Ozanne would see me at ten in the morning. She sounded as surprised as I felt. She then added that Colonel Pollock could not be present; he was away at a training school. That was a setback, because barristers have been known to take kindly to silk.
I spent half the night preparing for the appointment, the other half wishing I hadn’t made it. I needed a booster from Tommy and I tried to phone him but he was still at Duke Street in conference with Passy. I left a message for him to ring me if he possibly could. It was essential to be prepared for a total rejection from Ozanne and I tried to work out a contingency plan.
At one in the morning Tommy phoned. I told him of my appointment with Ozanne.
He instructed me to keep my voice up, not to smoke cigars, under no circumstances to make a joke – and above all to cut off my temper like a silk code and burn it before I went in. I promised to comply.
He then wished me ‘Merde alors!’ – the ultimate SOE benediction.
I’d need it with the ultimate SOE merde.
FIVE
All Things Bright and Beautiful
Hoping Ozanne had cancelled our appointment, I knocked on the door of his Norgeby House office and aged five minutes (the wartime equi-valent of as many years) when I was instructed to enter. He was seated behind a large desk covered with what I imagined were unread signals. The blackboard I’d asked for was a few feet away.
I imparted the good news that I’d come to show him how I believed the enemy would attack the poem-code, and he invited me to take all the time I needed; he had no other appointments for fifteen minutes.
I wrote out two coded messages, one on top of the other. Each message was fifty-five letters long, and by the time I’d given every pair of letters a number he was already consulting his watch.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Message 1:
C
N
A
E
R
S
S
N
G
E
O
O
N
N
Message 2:
T
H
I
S
T
E
P
F
N
D
S
L
O
A
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
Message 1 (cont.):
R
O
S
E
E
E
I
S
O
A
O
L
N
G
Message 2 (cont.):
O
Y
E
N
W
S
N
M
H
A
E
G
D
I
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
Message 1 (cont.):
C
E
E
E
E
E
R
E
T
D
L
S
Z
E
Message 2 (cont.):
E
P
B
E
K
S
T
K
U
G
I
G
D
S
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
Message 1 (cont.):
L
T
H
S
S
N
A
V
A
N
T
E
M
Message 2 (cont.):
U
U
S
E
E
A
T
R
N
C
C
O
E
I explained that the messages were mini-examples of our agents’ traffic. They’d been encoded on the same poem using the same five words and were of equal length. This all-too-frequent occurrence was every cryptographer’s wish-fulfilment as it gave him what was known in the trade as a ‘depth of two’.
I glanced round at him. He was reading a newspaper. ‘Quite,’ he said, peering over the top of it.
I asked him what words he thought a cryptographer would look for when he tackled an average SOE message and he picked up one of his signals.
‘Dropping grounds,’ he said, ‘and containers and moon periods. That sort of bumph.’
‘Yes, sir,’ I said encouragingly. ‘And “message begins” and “message ends” and “sorry about my indecipherable”, and that sort of bumph.’
I then suggested that the messages contained the names of some of SOE’s key figures, and that the enemy would try to anagram them. Whose names would they be most likely to start looking for?
After a modest pause he conjectured that his own might be one of them.
Thank God we’d got that far. I asked him if he considered rank to be important. He looked hard at me and agreed that it was. I wrote the words COLONEL OZEANNE on the blackboard.
‘You’ve spelled my name wrong, damn it.’
I apologised and tried to make capital out of it. ‘It’s an uncommon one, sir – but its letters aren’t, except for the Z. That’s the first letter they’d try to pinpoint. Is there a Z in either message?’
‘No.’
‘Sorry, sir. It must be my bad writing. What’s that letter in the top message under number 41?’
‘That’s supposed to be a Z, is it?’
‘Yes, sir, and that’s a D beneath it, in the bottom message. Those two letters must be tackled together. And that’s true of all the other pairs of letters in the messages, sir. That’s because both texts have been encoded on the same transposition keys and put through the same poem-code mangler. That makes our stint much easier, because instead of having to anagram each message separately, we can anagram them together. If we find a word in the top message, the letters in the bottom message should also make sense. If we find a word in the bottom message, the letters in the top message should also form one. So if “Colonel Ozeanne” is on top, we shall soon discover what you’ve got underneath you!’
I showed him what I meant before he had me arrested.
41
Top message:
C
O
L
O
N
E
L
O
Z
E
A
N
N
E
Bottom message:
D
The only Z in either message was at number 41 in the code groups and D was beneath it. So whatever word lay beneath ‘Ozeanne’, the letter D had to be part of it.
The first step in the anagramming was to write out his name with all the letters from the bottom message which fell beneath it:
Top message:
C
O
L
O
N
E
L
O
Z
E
A
N
N
E
Bottom message:
T1
S11
G26
S11
H2
S4
G26
S11
D41
S4
I3
H2
H2
S4
"
E29
L12
I39
L12
F8
D10
I39
L12
D10
A24
F8
F8
D10
"
Y16
U43
Y16
O13
N18
U43
Y16
N18
T49
O13
O13
N18
"
H23
H23
A14
W19
H23
W19
N51
A14
A14
W19
"
E25
E25
D27
S20
E25
S20
D27
D27
S20
"
A48
P30
P30
A48
A48
P30
"
C52
B31
B31
C52
C52
B31
"
E32
E32
E32
"
K33
K33
K33
"
S34
S34
S34
"
K36
K36
K36
"
S42
S42
S42
"
O54
O54
O54
Cryptographers on a diet of alphabet soup would quickly recognise familiar ingredients, but Ozanne’s appetites lay in other directions and I asked him to look first at the letters beneath the word COLONEL. Were there any words forming? Or familiar combinations of letters? TH, for example, or ER or ON or AN or RE? Was there anything promising under COLON? He told me what he usually found there and finally volunteered that he could see the word THIS. The coders of Grendon would have spotted THUS as well, but at least we’d begun.
Top message:
C
O
L
O
N
E
L
O
Z
E
A
N
N
E
Bottom message:
T1
S11
G26
S11
H2
S4
G26
S11
D41
S4
I3
H2
H2
S4
"
E29
L12
I39
L12
F8
D10
I39
L12
D10
A24
F8
F8
D10
"
Y16
U43
Y16
O13
N18
U43
Y16
N18
T49
O13
O13
N18
"
H23
H23
A14
W19
H23
W19
N51
A14
A14
W19
"
E25
E25
D27
S20
E25
S20
D27
D27
S20
"
A48
P30
P30
A48
A48
P30
"
C52
B31
B31
C52
C52
B31
"
E32
E32
E32
"