I was taken to Dilly Knox’s section, in the cottage. It was very much a research unit. Hut 6 was up and running and operational, but Dilly had been one of the great pioneers of it all. He was working on things that hadn’t been broken. It was a strange little outfit in the cottage because… well, organisation is not a word you would associate with Dilly Knox. When I arrived, he said: ‘Oh, hello, we’re breaking machines, have you got a pencil?’ That was it. I was never really told what to do. ‘Here you are, here’s a whole load of rubbish, get on with it.’ I think looking back on it that was a great precedent in my life, because he taught me to think that you could do things yourself without always checking up to see what the book said. That was the way the cottage worked. We were looking at new traffic all the time or where the wheels or the wiring had been changed, or at other new techniques. So you had to work it all out yourself from scratch.
Knox had a unique knack of using his imagination to open up codes and cyphers. ‘He would stuff his pipe with sandwiches sometimes instead of tobacco he was so woolly-minded,’ Lever said.
But he was brilliant, absolutely brilliant. It just seemed to come naturally to him. He said the most extraordinary things. He was a great admirer of Lewis Carroll, ‘Which way does the clock go round?’ And if you were stupid enough to say clockwise, he’d just say: ‘Oh, no it doesn’t, not if you’re the clock, it’s the opposite way.’ And that’s sometimes how you had to think about the machines. Not just to look at them how you saw them but what was going on inside. That was the only way in which one was really trained. But trained is a bad word because that was the one thing you mustn’t be. You have got to look at each thing afresh and wonder how you could approach it.
The need to look at codes and cyphers from different perspectives was drummed into Knox’s assistants and served both Lever and the Royal Navy well when she spotted one missing element in a long Italian Naval Enigma message.
The one snag with the Enigma of course is the fact that if you press A, you can get every other letter but A. I picked up this message and – one was so used to looking at things and making instant decisions – I thought: ‘Something’s gone. What has this chap done. There is not a single L in this message.’ My chap had been told to send out a dummy message and he had just had a fag and pressed the last key of the middle row of his keyboard, the L. So that was the only letter that didn’t come out. We had got the biggest crib we ever had, the encypherment was LLLL right through the message and that gave us the new wiring for the wheel. That’s the sort of thing we were trained to do – instinctively look for something that had gone wrong or someone who had done something silly and torn up the rulebook.
The keys she uncovered as a result of the Italian operators’ mistake were to provide the Royal Navy with its first major victory of the war. Messages decyphered by Lever provided details of the Italian Navy’s plans to attack British ships off the Greek coast and led to a Royal Navy victory at the Battle of Matapan.
‘We didn’t often know the results of our activities, which messages were important,’ Lever said.
Because you see you might actually break a message which said nothing to report which would give you the settings for the rest of the messages. But the Italian messages were done individually. The first Matapan message was very dramatic stuff: ‘Today’s the day minus three’, just that and nothing else. So of course we knew the Italian Navy was going to do something in three days’ time. Why they had to say that I can’t imagine. It seems rather daft but they did. So we worked for three days. It was all the nail-biting stuff of keeping up all night working. One kept thinking: ‘Well, would one be better at it if one had a little sleep or shall we just go on,’ and it did take nearly all of three days.
Then a very, very large message came in which was practically the battle orders for what turned into the Battle of Matapan. How many cruisers there were, and how many submarines were to be there and where they were to be at such and such a time, absolutely incredible that they should spell it all out. It was rushed out to Cunningham and the marvellous thing about him was that he played it extremely cool. He knew that they were going to go out and confront the Italian fleet at Matapan but he did a real Drake on them.
The Italian intention was to intercept British convoys en route from Egypt to Greece. Such was the Royal Navy’s superiority over the Italians that Cunningham initially did not believe the Italians would dare to carry out these plans, but pressure was applied from the Admiralty to ensure that he did believe it. Knowing that the Japanese Consul in Alexandria, who was reporting on the movement of the Mediterranean Fleet, was a keen golfer, the British admiral ostentatiously visited the club house with his clubs and an overnight bag. ‘He pretended he was just going to have the weekend off and made sure the Japanese spy would pass it all back,’ Lever recalled. ‘Then under cover of the night, they went out and confronted the Italians.’
In a series of running battles over 27 and 28 March 1941, Cunningham’s ships attacked the Italian flotilla sinking an entire Italian cruiser squadron of three Italian heavy cruisers and two Italian destroyers with the loss of 3,000 Italian sailors. Without radar, the Italians were caught completely by surprise, Lever recalled.
It was very exciting stuff. There was a great deal of jubilation in the cottage and then Cunningham himself came to visit us with Admiral Godfrey to congratulate us in person. We rushed down to the Eight Bells at the end of the road to get some bottles of wine and if it was not up to the standard the Commander-in-Chief Mediterranean was used to he didn’t show it. The cottage wall had just been whitewashed. Now this just shows how silly and young and giggly we were. We thought it would be jolly funny if we could talk to Admiral Cunningham and get him to lean against the wet whitewash and go away with a white stern. So that’s what we did. It’s rather terrible, isn’t it? On the one hand, everything was so very organised and on the other these silly young things are trying to snare the admiral. We tried not to giggle when he left. He had shaken us all warmly by the hand and we thought that was the end of Matapan. It was in fact practically the last we would hear of the Italian fleet, which only made one more appearance before surrendering to Admiral Cunningham in 1943.
Despite the British victory at Matapan, German troops, supported by the Luftwaffe, executed yet another Blitzkrieg through Yugoslavia and into Greece. British and Greek troops facing insuperable odds were forced to retreat. But the campaign was the first in which the intelligence unearthed by the Bletchley Park codebreakers could be passed on to the commanders in the field direct from Bletchley Park itself rather than through MI6, as had occurred in Norway and France.
A direct ‘Special Signals Link’ had been set up between Bletchley Park and Cairo in early 1941 to feed the Ultra intelligence to the British forces in the Middle East and it was extended to the British headquarters in Athens shortly before the German invasion. The Red Luftwaffe key provided comprehensive details of the discussions of the German Fliegerverbindungsoffiziere or Flivos, the air liaison officers who coordinated air and ground operations, and although this had to be passed on in a highly sanitised fashion, it ensured that the British could make an orderly retreat.
It also gave early warning that German airborne forces were moving to the Balkans in preparation for the invasion of Crete. A series of messages beginning in late March provided the British with every detail of the operation, from the preparations to the complete plan of the airborne assault, and the day, 20 May, on which it was to be launched. The problem was to find a plausible way of camouflaging the source of all this intelligence so as to ensure the Germans did not realise that Enigma had been broken.
On Churchill’s orders, Hut 3 produced a detailed report purporting to be a complete dossier of the German plans obtained by an MI6 agent inside the German GHQ in Athens. This was sent to Cairo over the special Middle East link and then passed to General Bernard Freyberg, the New Zealand Commander in Crete, encyphered in the virtually unbreakable ‘one-time pad’ cypher s
ystem. Although Freyberg did not have the resources to fight off a sustained attack, the knowledge garnered from the ‘German documents’ robbed the Germans of any element of surprise – Freyberg allegedly looked at his watch when the German paradrop began and said: ‘Right on time.’ Alerted by the codebreakers, his men were able to pick off the enemy paratroopers at will, causing carnage and considerably delaying the inevitable defeat.
‘Crete was an example of how knowing a great deal, through the Red, didn’t necessarily lead to the correct results,’ said John Herivel.
All the German plans, the details for the invasion of Crete were known through Hut 6 decodes on the Red. We all knew about the German plans for the airborne assault on Crete – because there was no attempt to stop the people in Hut 6 from knowing what was in the decodes – and therefore we felt very confident that we would defeat it. But in fact we didn’t. What did happen was that they had such enormous difficulty in taking Crete and suffered such enormous losses that Hitler decided he wouldn’t try a parachute descent in that strength again.
The tendency of the Admiralty’s Operational Intelligence Centre (OIC) to ignore much of what Bletchley Park Naval Section said reappeared in April and May of 1941 during an event that was to have a dramatic effect on morale at Bletchley Park – the sinking of the Bismarck. The battleship, the showpiece of the German navy, had been in the Baltic since her completion the previous September. The Admiralty was watching and waiting for her to break out into the Atlantic to attack the Allied convoys bringing supplies to Britain.
Early indications that the Bismarck was about to leave the Baltic came in decrypts of the Red Enigma which showed that the Luftwaffe was mounting a close watch on the activities of the British Home Fleet anchored in Scapa Flow. An MI6 agent was dispatched to monitor the passage of ships through the Kattegat, the narrow strip of water separating Denmark from Sweden, and, on 20 May, he reported that two large German warships had left the Baltic bound for the North Sea. The sighting was confirmed by photographic reconnaissance and a few isolated breaks into the main Naval Enigma cypher showed that the Bismarck, accompanied by the new cruiser the Prinz Eugen, was about to attack Britain’s transatlantic trade routes.
A British naval squadron was dispatched to hunt the Bismarck down. She was sighted on the evening of 23 May and next morning was engaged by the Hood and the Prince of Wales. The Hood was sunk and the Prince of Wales hit but not without the Bismarck herself sustaining some damage. She parted company with the Prinz Eugen and the Royal Navy ships lost contact with her. Throughout the following day there was confusion as to what direction the Bismarck was travelling in. The repeated insistence by Bletchley’s Naval Section that the Bismarck was heading for the safety of a French port was ignored. Hinsley had telephoned the OIC following the engagement to tell the duty officer that radio control of the Bismarck had switched from Wilhelmshaven to Paris, a clear sign that she was sailing south towards France. It was not until the early evening of 25 May, following yet another heated telephone conversation between Hinsley and the OIC, that this reasoning was finally accepted.
The manner and speed of its confirmation were to become a part of the Bletchley folklore. Just minutes after Hinsley’s angry exchange with the Admiralty, Hut 6 decyphered a message on the Red Enigma from General Hans Jeschonnek, the Luftwaffe Chief of Staff, who was concerned over the fate of a relative, a member of the Bismarck’s crew. He was told that the battleship was making for the safety of Brest. Armed with this news, Royal Navy ships of both the Mediterranean and Home Fleets closed in on her. When aircraft from the Ark Royal succeeded in jamming her rudder on the evening of 26 May, her fate was sealed. In messages only decrypted after she had been sunk, Admiral Lutjens, the officer commanding the Bismarck, signalled: ‘Ship unmanageable. We shall fight to the last shell. Long live the Führer.’
The success against the Brown Enigma, which prepared the RAF fighter aircraft to take on German bombers during the Blitz, was highly secret and not known to many of the staff, whereas the sinking of the Bismarck had involved not only Hut 6 and Hut 3, but also the Naval Section Hut 4, using intelligence that didn’t come from Enigma. So for most of those working at Bletchley this was the first time they had seen tangible evidence of the effect they could have on the war. News of the codebreakers’ role in the affair swiftly got around the Park raising morale and giving them a real feeling of making a contribution to the war effort. Malcolm Kennedy was in the dining room in the mansion at Bletchley Park when the news came through on the one o’clock news that she had been sunk. ‘Spontaneous cheering and clapping broke out from those at lunch when the announcement was made,’ he said, ‘though some of us had heard the good news slightly before. To give the devil his due, Bismarck put up a very good show.’
Years later, Mavis Lever took her son to see the film Sink the Bismarck.
I saw it go down and suddenly I really did feel quite sick. I put my head down and my son said to me after a while: ‘It’s alright Mummy, it’s gone down.’ He didn’t know. But I was thinking how awful it was that one’s breaking of a message could send so many people to the bottom. But that was war and that was the way we had to play it. If we thought about it too much we should never have been able to cope.
Throughout the campaign in the Balkans, Railway Enigma had been indicating a series of movements, named after famous actors and film stars, heading north and east towards Poland. During March, April and May, message after message on links using the Red cypher pointed to a major concentration of German troops and air support converging on an assembly point at Oderberg, near Krakow. While much of the movement could have reflected a German attempt to intimidate Moscow, as many in Whitehall were inclined to believe, the inclusion of a prisoner-of-war interrogation unit and the urgency with which units were being pulled out of the Balkans convinced the codebreakers that the Germans were about to turn on their Russian allies.
‘It becomes harder than ever to doubt that the object of these large movements of the German Army and air force is Russia,’ said one long-term report issued by the Hut 3 research section in early May.
From rail movements towards Moldavia in the south to ship movements towards Varanger fjord in the far north there is everywhere the same steady eastward trend. Either the purpose is blackmail or it is war. No doubt Hitler would prefer a bloodless surrender. But the quiet move, for instance, of a prisoner-of-war cage to Tarnow looks more like business than bluff.
It was not until 10 June, when the Japanese diplomatic section translated a message to Tokyo from the Japanese ambassador in Berlin confirming that the invasion was imminent, that Whitehall finally accepted, amid a welter of evidence from Ultra decrypts emanating from Hut 6, that the codebreakers had got it right. Twelve days later, Hitler launched the aptly named Operation Barbarossa, the invasion of the Soviet Union. It was to bring some of the most distressing decrypts the codebreakers were to handle at any point of the war.
The messages of the SS and the Ordnungspolizei, the ordinary uniformed German police, who were mopping up behind the German lines during Operation Barbarossa make chilling reading, providing details of the systematic murder by the advancing German forces of thousands of Jews. The first news of these killings was read at Bletchley Park. On 18 July 1941, Army intercept operators based temporarily at Chicksands picked up a message from Obergruppenführer Erich von dem Bach-Zelewski, Ordnungspolizei commander in the Soviet republic of Belorussia, to Kurt Daluege, head of the Ordnungspolizei, and Heinrich Himmler, the Reichsführer-SS, or head of the SS.
The cypher in use was a basic double transposition cypher. In a transposition cypher, the letters that make up the text of the message are shuffled in some pre-determined way. As the name suggests, in a double transposition system, the order of letters produced by the initial process is shuffled a second time. It was broken relatively easily by Bletchley Park, originally by Tiltman, but thereafter in routine fashion in Hut 5.
Von dem Bach-Zelewski’s message read: ‘In yes
terday’s cleansing action in Slonim, carried out by Police Regiment Centre, 1,153 Jewish plunderers were shot.’ (Slonim is a town in south-west Belorussia, midway between Warsaw and Minsk.)
On 4 August von dem Bach-Zelewski reported that in further mopping-up operations in an area south of the Belorussian town of Pinsk his men had shot dead ‘ninety Bolsheviks and Jews’. Later the same day, he reported that his SS Cavalry Brigade was still removing opposition in the region north to north-east of Lake Sporowski. ‘As at the evening of 3 August the SS Cavalry Brigade had liquidated 3,274 Partisans and Jewish Bolsheviks. Police Battalion 306 has shot dead 260 guerrillas,’ he said. Three days later von dem Bach-Zelewski reported that the SS Cavalry Brigade was now pushing further forwards. ‘By midday today a further 3,600 had been executed, so that the complete total for those executed by the brigade is now 7,819. This brings the total in my area to more than 30,000.’ His apparent determination to make as much of the killings as possible was such that one Bletchley Park analyst noted: ‘The tone of this message suggests that word has gone out that a definite decrease in the total population of Russia would be welcome in high quarters and that the leaders of the three sectors stand somewhat in competition with each other as to their scores.’
It is worth noting that the Ordnungspolizei were ordinary uniformed police officers, the same police officers who are supposed to protect people against crime and in whom most normal law-abiding people in civilised countries place their trust. There were three main German formations, roughly speaking, mopping up behind the German lines. Von dem Bach-Zelewski’s men were the central formation, operating in Belorussia. There was a northern formation designated to carry out mopping-up operations in the Baltic republics, and another through the Ukraine in the south. At the heart of each formation was an Einsatzgruppe, or task force, made up largely of members of the Gestapo and Sicherheitspolizei, the Security Police, and split into four separate Einsatzkommando. It was the Einsatzgruppe of each formation that was expected to orchestrate the bulk of the killings. But messages decyphered by Bletchley Park very soon showed that the ordinary police units, as well as of course the SS troops, were heavily involved in the killings.
The Secrets of Station X Page 13