The Secrets of Station X

by Michael Smith

  Tester recalled long conversations with Flowers, Turing, Tutte and Newman over what should be done. Flowers, who had been developing telephone exchanges containing valves instead of the old fashioned relays used in Robinson, suggested that he could make an electronic machine built with valves that would do the same job much faster without the need for the synchronisation of the two tapes. The data on the wheel patterns would be generated electronically using ring circuits while the tape reading the cypher text would be read photo-electrically and could be run on smooth wheels rather than sprockets so it wouldn’t rip.

  The codebreakers asked Flowers how long it would take to produce the first machine. ‘I said at least a year and they said that was terrible,’ Flowers recalled. ‘They thought in a year the war could be over and Hitler could have won it so they didn’t take up my idea. They decided they would proceed hopefully with the Robinson.

  I was so convinced that Robinson would never work that we developed the new machine on our own at Dollis Hill. We made the first prototype in ten months, working day and night, six-and-a-half days a week, twelve hours a day sometimes. We started with the design of what was to be called Colossus in February 1943 and we had the first prototype machine working at Bletchley Park on 8 December.

  The purpose of the Colossus was to find out what the positions of the code wheels were at the beginning of the message and it did that by trying all the possible combinations and there were billions of them. It tried all the combinations, which processing at 5,000 characters a second could be done in about half an hour. So then having found the starting positions of the cypher wheels you could decode the message.

  Flowers said the codebreakers were astounded at how reliable it was compared to Robinson.

  What they did with Colossus, the first day they got it, was to put a problem on it which they knew the answer to. It took about half an hour to do the run. They let it run for about four hours, repeating the processes every half hour, and to their amazement, it gave the same answer every time. They really were amazed. It was that reliable, extremely reliable.

  Colossus was the world’s first large-scale electronic digital computer and as such the forerunner of the computers most people use today. It was also the first to be programmable, albeit as a result of its specialised role, semi-programmable. Although it had a specialised function, it showed the theory could be turned into practice. The sequence of operations was determined mainly by the setting of external switches and plugboards, which were controlled by Wrens on the orders of the Newmanry codebreakers. Just like the Robinson, it was looking for sequences that were not random.

  ‘The work on Tunny divided roughly between what you might call the machine work and the hand work,’ said Peter Hilton.

  Machine work was of course putting messages on to Colossus which was a process whereby we would determine the starting positions of the first set of five wheels which were involved in making up the key. Then after that process had taken place, that is to say a process based on statistics, mathematics, the message shorn of part of its key, would come to the codebreakers in the Testery who would then have the job of using their knowledge of expected pieces of text in order to set the remaining wheels.

  Each codebreaker was assisted by two Wrens who set the machine up. Jean Thompson was just nineteen when she was posted to Bletchley in 1944 to work on Colossus.

  Most of the time I was doing wheel setting, getting the starting positions of the wheels. There would be two Wrens on the machine and a duty officer, one of the cryptanalysts – the brains people, and the message came in on a teleprinted tape.

  If the pattern of the wheels was already known you put that up at the back of the machine on a pinboard. The pins were bronze, brass or copper with two feet and there were double holes the whole way down the board for cross or dot impulses to put up the wheel pattern. Then you put the tape on round the wheels with a join in it so it formed a complete circle. You put it behind the gate of the photo-electric cell which you shut on it and, according to the length of the tape, you used so many wheels and there was one moveable one so that could get it taut.

  At the front there were switches and plugs. After you’d set the thing you could do a letter count with the switches. You would make the runs for the different wheels to get the scores out which would print out on the electro-matic typewriter. We were looking for a score above the random and one that was sufficiently good, you’d hope was the correct setting. When it got tricky, the duty officer would suggest different runs to do.

  Another of the Wrens working in the Newmanry was Odette Murray.

  I was offered the chance of joining what was known as Pembroke V, not knowing what it was all about. A group of us turned up at Bletchley Park where we were taught to be touch typists, still not knowing what it was all about, and eventually I got into the park itself in the Newmanry. I was head of a watch and I was given instructions by whoever was in charge at the time and, still not having the remotest idea what I was doing, I worked with a slide rule producing a lot of figures and gave the result to the next person who gave it to the next person and eventually it was run on a tape.

  Shaun Wylie had just been transferred over from Hut 8 shortly after Odette Murray arrived at Bletchley. ‘All the Wrens were swooning about Shaun Wylie,’ she recalled.

  They thought he was absolutely wonderful: ‘Oh, Mr Wylie this, oh Mr Wylie that.’ I didn’t think much of him. I couldn’t see what they saw in him. However, he thought something of me.

  He tried to explain to me exactly what my contribution had been in a successful thing. I just didn’t understand. I’m not a mathematician, I’m not a linguist. I’m just somebody who’s given instructions and does little funny calculations with a slide rule and bingo. A few days later a smiling Shaun comes in. I don’t know what my contribution is but okay, satisfactory.

  She was billeted in Woburn Abbey and on their days off Wylie would cycle over there to visit her. ‘Most of our courting was in Woburn Park,’ Odette recalled.

  The Abbey is a huge imposing building and the central part has a large podium on top of it, very high up, and I used to go casual climbing, leaping across two-foot, three-foot chasms so that I could sit on the top of this to watch Shaun on his bicycle coming up the drive. No way would I go up there now.

  The atmosphere in the Newmanry was very happy, largely because of Newman’s influence. ‘Max Newman was a marvellous fellow,’ American codebreaker George Vergine recalled.

  I always sort of felt grateful to have known him really. We used to have tea-parties. These were just discussions on problems or developments, techniques, to a great extent mathematical. We used to meet in the small conference room. Somebody would write a topic up on the blackboard and all of the analysts, including Newman, would come with their tea in hand and chew it around and see whether or not it would be useful as far as cracking more communications. They were very productive and after it was over somebody would summarise it in the research log.

  Once the encyphered messages had been stripped of the effect of the first set of wheels, the part-decyphered message was passed to the Testery where the cryptanalysts worked out the setting of the second row of wheels. The work in the Testery was much more like that in Huts 6 and 8 where the Enigma material was decyphered. The human brain had to take over from the machine.

  ‘We had to operate on a semi-intuitive basis and sometimes your intuition worked and sometimes it didn’t,’ said Roy Jenkins.

  It was a curious life. It could be very wearing, particularly if it didn’t succeed. You could spend nights in which you got nowhere at all. You didn’t get a single break, you just tried, played around through this bleak long night with total frustration and your brain was literally raw. I remember one night when I made thirteen breaks. But there were an awful lot of nights when I was lucky if I made one. So it was exhausting.

  The codebreakers looked for differences between the Baudot elements for regular sequences of letters which occur commonl
y in German, or characters that denoted a common sequence of teleprinter instructions.

  One of the methods used in the Testery to get into the Tunny transmissions originated from the tests conducted by the German operators before sending the message, Peter Hilton recalled.

  We were fortunate that the Germans seemed to have been so convinced that we couldn’t possibly be reading Tunny that they didn’t take the precautions they should have done.

  At the beginning of each message, the German operator would transmit by hand some little piece of text of his own in order that the other operator would be able to report: ‘I am receiving you clearly.’ He could then switch over from hand transmission to automatic and put through the tape of the real message. Some of the German operators began to reveal their own personalities by referring to their own conditions and circumstances.

  I remember one message which the operator began: ‘Mörderische Hitze’ – murderous heat. Well once I’d broken the first few letters to guess he was talking about mörderische and it was quite likely, because that’s a sort of natural expression of an ordinary German when something is terribly bad. What could be bad? He was writing from southern Italy, so it was very likely it would not be the food. It was probably the heat.

  So you got to know people. There was another one I remember from outside Leningrad who said: ‘Ich bin so einsam’ – I’m so lonely. The next day came a message that said: ‘Hier ist so traurig’ – It’s so sad here, and this fellow, I had the feeling that he didn’t want to be there. He didn’t want to be fighting the Russians. He didn’t want to be besieging Leningrad, but he had to do it.

  The officers drafting the messages made equally stupid mistakes, repeating predictable, and often completely useless, phrases, Hilton said.

  I remember ‘Nieder mit den Englander’, down with the English, as a phrase that certainly appeared very commonly in these messages and of course ‘Heil Hitler’ was enormously valuable. You should never inculcate in your military the tendency to have exactly the same phrase opening every statement.

  Once the settings of both rows of wheels had been worked out, the tape of the encyphered message was taken into the Tunny Room where there were a number of ‘Tunny machines’ that had been built at Dollis Hill to replicate the action of the Lorenz cypher machine. The machine was set up in exactly the same way as the German cypher machine was set up and the clear language German came out.

  Since they were Army messages, they were then passed to the Hut 3 intelligence reporters. The first really important reports to result from the decyphered Tunny messages covered the Eastern Front. They came between April and July 1943 when the complete German plans for the forthcoming Battle of Kursk were sent on the link between the headquarters of the German Army Group South and Berlin. A sanitised version, disguising the source, was passed to Moscow but this assistance was unnecessary. Stalin was already receiving full transcripts. Despite the strict security in force at Bletchley Park, a member of one of the watches in Hut 3 was a KGB spy.

  John Cairncross, codenamed Liszt by the Russians because of his love of music, had already given Moscow Centre details of Bletchley Park’s network of intercept sites while working in the section of the Treasury that dealt with the GPO in the months before the war. He had then become private secretary to Lord Hankey, the Minister without Portfolio, and passed the Russians details of the Anglo-American atomic weapons project, providing them with the information that formed the basis for their own atomic weapons programme.

  But at the beginning of 1942, Cairncross was called up and was instructed to try to get himself into Bletchley Park, which the KGB codenamed Kurort (German for Spa). Moscow Centre was aware from one of its other agents that Colonel Frederick Nicholls, the head of MI8, was looking for new codebreakers and told Cairncross to seek him out. ‘In the course of his professional duties, Liszt became acquainted with Nicholls and by rendering small services established friendly relations with him,’ Cairncross’s KGB handler told the Centre.

  During lunch at the Travellers Club, Liszt complained to Nicholls that he was about to be called up by the Army where he would be unable to use his knowledge of foreign languages. Nicholls started to persuade him to come to work in Kurort. After he received his call-up papers, Liszt told Nicholls about this, remained in his unit for one day and was then put at the disposal of the War Office which conditionally demobilised him and seconded him to Kurort.

  Cairncross smuggled decrypts that were due to be destroyed out of Hut 3 in his trousers, transferring them to his bag at the railway station before going on to London to meet his KGB contact. The information that he handed the Russians is probably rightly credited with helping them to win the Battle of Kursk, the turning point on the Eastern Front. Despite the fact that a sanitised version of the Tunny messages was being passed to Moscow, Stalin was highly suspicious of any intelligence passed to him by the Allies, particularly if the source was unclear. But Cairncross was supplying the German language signals and it was coming via the KGB. ‘The Russians were convinced,’ Cairncross said, ‘that in its German version the Ultra I supplied was genuine, giving the full details of German units and locations, thus enabling the Russians to pinpoint their targets and to take the enemy by surprise.’

  It is impossible to tell how vital his contribution to the Battle of Kursk was. But the Russians’ codes were being decyphered by the Germans and their brief liaison with Hitler had left them riddled with Nazi agents. His breaching of the Ultra secret risked informing the Germans that their most secret cypher systems had been broken.

  The surrender of Italy saw all the linguists and codebreakers who were working on Italian codes and cyphers switched to Japanese systems and two separate Japanese courses were set up, one in Bedford by Tiltman and another by Josh Cooper’s Air Intelligence Section which required linguists capable of listening to the clear speech passing between pilots and their ground controllers. Cooper’s eccentric approach was reflected in the course he selected for his Japanese students. It was described by Tiltman, with some understatement, as ‘a rather more tricky experiment’ than the Bedford course.

  What the Royal Air Force needed was interpreters who could read air-to-ground and air-to-air conversations. For this purpose my counterpart in the Air Section J. E. S. Cooper started an intensive 11-week course at which the students were bombarded incessantly with Japanese phonograph records, ringing the changes on a very limited vocabulary. The course was directed, not by a Japanese linguist, but by a phonetics expert. I remember taking a US Army Japanese interpreter, Colonel Svensson round the course. Stunned by the volume of sound in every room, Svensson mildly asked the Director whether all the students made the grade and the reply he received was: ‘After the fifth week, they’re either carried away screaming or they’re Nipponified.’

  The British codebreakers from the Far East Combined Bureau had moved from Singapore first to Colombo and then, in April 1942, to Kilindini, near Mombasa in Kenya, and in September 1943 back to Colombo. Although the Americans dominated the day-to-day breaking of Japanese codes and cyphers, it was the British who ‘broke in’ to most of them with John Tiltman leading the way. Having broken the main military encyphered code systems in 1938, he had followed that up with the main Imperial Japanese Fleet encyphered code, JN25, the Japanese Military Attaché code in mid-1942 and the Japanese Army Air Force General Purpose Code in early 1943. Other important Japanese codes were broken by British codebreakers in Kilindini and Delhi. Of the major Japanese codes and cyphers, the Americans ‘broke into’ only very few, but one of these was one of the most important, the Purple Japanese diplomatic machine cypher, and it was inevitably the Americans who made the most spectacular use of the Allied breaks into Japanese codes and cyphers, most emphatically before the Battle of Midway, in June 1942, when the US Navy codebreakers at Pearl Harbor decyphered the entire Japanese battle plan.

  The number of Japanese sections increased dramatically in late 1943, with one long corridor in F Block known
as the Burma Road because of the large number of Japanese sections all along it. Most of the sections dealing with Japanese Army material were a mixture of Intelligence Corps personnel, Foreign Office civilians and members of the Women’s Auxiliary Territorial Service (ATS), many of whom did extremely repetitive work preparing messages for the codebreakers to tackle. Gladys Sweetland was sent to the mysterious ‘Station X’ as a young ATS corporal.

  ‘I went for an interview at a place in Praed Street, in London,’ she said.

  We were there for several days being interviewed by lots of different people, most of them officers. Then finally we were told we were being transferred to Bletchley. It was really rather weird. I was taken into a hut and introduced to what I was supposed to do. Teleprinter sheets of coded messages were handed to me and I had to copy each message out in different coloured inks across one line on large sheets of graph paper, a bit tricky when some stretched across four different sheets. Each message was marked with a sign to indicate which colour ink I should use. I know it sounds ridiculous but we never asked what they did with the sheets of messages. It was all so secret. Even with the other girls in the ATS we only ever asked: ‘Where do you work?’ And they’d say: ‘Oh, Hut 6’ or ‘Block F’ or whatever. We never asked each other what we actually did.

  We were given travel passes to come in by train during the day, which was similar to going to and from work in ‘Civvy Street’ and it was fairly easy. When we finished at midnight there was a bus which would take a whole load of us home, dropping everyone off at the various villages where they were billeted and it depended on how many of you there were, and what route the bus took, how long it took you to get home. The first woman I was billeted with was rather peculiar. She had two young children and wanted me to stay in and look after them all the time so she could go out. The second was much nicer. She was middle-aged. She had a son who was in the RAF and her attitude was that if she could treat people billeted with her kindly, then perhaps other people would treat her son the same way. She would insist on bringing me breakfast in bed after I had worked the late shift.