The Bletchley Park Codebreakers (14 page)

When I appeared on the scene in early May 1940 the unit was still small and consisted of Jean Perrin, Clare Harding, Rachel Ronald and Elisabeth Granger, but our numbers would soon increase. I had been reading German at University College, London, but didn’t feel I should be evacuated to Aberystwyth to continue my studies in German romantic poets, and said I would train as a nurse. However, somebody stepped in and I was sent first to Broadway and then, when the phoney war ended, to the expanding Bletchley. When Penelope Fitzgerald, Edmund ‘Evoe’ Knox’s daughter, was writing her book.
The Knox Brothers
, she asked me if I could remember her uncle’s first words to me and my introduction to breaking Enigma. I recalled they were: ‘Hello, we’re breaking machines. Have you got a pencil.? Here, have a go.’ I was then handed a pile of utter gibberish, made worse by Dilly’s scrawls all over them. ‘But I am afraid it’s all Greek to me,’ I said, at which he burst into delighted laughter and replied, ‘I wish it were’. I couldn’t understand what Penelope meant when she said, ‘Half a moment; you know what you are saying, don’t you? That’s exactly what Alice said when she met Dilly for the first time in Room 40 in World War I.’ She then produced a copy of
Alice in ID2S,
which I have treasured ever since. At the time we were sitting in my husband’s rooms at Christ Church overlooking Alice in Wonderland’s Deanery garden.

I have always felt a bond with Dilly, who was for me Alice’s White Knight, endearingly eccentric and concerned about my welfare. Staying with the Knoxes at their Chiltern home of Courns Wood is a particularly happy memory, except for the horrendous drive from Bletchley with Dilly gesticulating and quoting Herodas and
‘
himmliche Rosen
’ ad lib, with total disregard of the oncoming traffic. Dilly was not a good driver. He had asked me over at that time as the avenue he had planted, aligned on the guest room, with alternating Scots pine and wild cherry, was then in full flower – a wonderful sight. Olive Knox was most apologetic that the laundry hadn’t turned up and she hadn’t been able to change the sheets. ‘I’m awfully sorry,’ she said, ‘but it was Ronnie who was in them last and he’s very clean.’ Dilly ventured the information that his brother was a ‘Roman’ and that he was helping him with translating his new version of the Bible. A remarkable family – Dilly, Evoe, Wilfred and Ronnie – by any standards, as Penelope Fitzgerald has shown in her book.

May 1940 was perhaps the tensest month in Britain’s history. It was brought home starkly to us when after Dunkirk the trains taking exhausted soldiers up north all stopped at Bletchley on the way. Bletchley Park was right near the station and a cry went out from the forces canteen for help. I remember the smell of my hair after I had cooked my ‘finest hour’ chips in between shifts all day. The fierce woman in charge had ordained that the young girls should be confined to the kitchen stove out of sight and that only the godly matrons would take out the tea and the chips to the troops in the trains. We thought that they would have preferred it the other way round; certainly we would have done. Before the canteen was built we all ate in the hall of the mansion and I remember that I was sitting next to a Frenchman when the fall of Paris was announced over the radio. I wasn’t sure what to do when he burst into tears so I went on eating my sausages; he must have thought me heartless, but with a long shift ahead and now the possibility of invasion, starving wouldn’t have helped.

In June Mussolini joined the war and it was imperative to find out which of the Enigma machines he would be using; fortunately for their Naval High Command, or
Supermarina
as we would soon find it was called, it proved to be the machine without a plugboard, used by the Italian Navy in the Spanish Civil War – for which Dilly had already worked out his theoretical rodding solution. Having the rods for each wheel may seem to make the problem trivial but it was a very tedious process to set up twenty-six positions for each of the three wheels in turn without a reliable crib to limit the possibilities. When traffic is broken cribs greatly assist any kind of subsequent decipherment, especially rodding. Our messages were infrequent so that there was
not the advantage of having several on the same setting on a day as there had been with Dilly’s Spanish traffic.

Having no such easy ‘ways in’, Dilly suggested that we should try something as simple as PERX (for) at the beginning of each message, disregarding those that ‘crashed’ (that is to say, had those letters in the enciphered text where the crib was needed, it not being possible for a letter to encipher as itself). The encoded text was written out on squared paper across the page and the appropriate rods set up under it, the letters on the rod fitting the same size squares. This went on tediously and unsuccessfully for months until finally, alone on the evening shift, I disobeyed instructions and when S, rejecting X, appeared of its own accord from the first coupling I did not discard the position but decided that PERSONALE might pay off as a guess. It did. Fortunately there was a run before the wheel turnover and a ‘beetle’ (two letters side by side), which meant that one of the remaining bigrams in the column would have to be used, suggesting other words to try. I was able to take this word over the turnover and so put up a new set of couplings on the other side. I then began to get an idea of how the machine really worked and, just as Dilly had said, got down to breaking it with a pencil. I have recently read Turing’s ‘Treatise on the Enigma’ in relation to breaking by rodding and feel sure that if I had seen it then I would have decided it was all too difficult. However, it seemed obvious enough that evening and I just took the couplings from one side of the turnover and found a position on one of the other wheels where the other couplings would lie side by side and then everything fell into place. Being trained on Dilly’s
Alice in Wonderland
thought processes was, it seems after all, better than wrestling with a Turing treatise. Dilly was amazed in the morning to find that I had produced not just the right-hand position of the wheel as instructed but the whole setting and had read the message. I was promoted which was a relief as I was only getting thirty shillings (£1.50) a week and had to pay a guinea (£1.05) for my billet.

The good thing was the psychological effect of knowing that we were no longer working in the dark and that we had the right machine. A few months later, however, to increase security,
Supermarina
changed the wiring of one of the wheels but a slack operator soon gave us a perfect crib, which enabled us to ascertain the new wiring. As soon as I picked up one long message, I could see that it had no L in it; as traffic was so infrequent operators were told to send out the
occasional dummy message and this one had just put his finger on the last letter of the keyboard, probably relaxing with a fag in his mouth. The usual Saga method of recovering the wiring by ‘buttoning up’ on the QWERTZU diagonal was proving very difficult owing to the repetitive nature of the crib. Once again I was alone on the evening shift in the Cottage and this time I sought the help of what Dilly called ‘one of the clever Cambridge mathematicians in Hut 6’; as luck would have it, it was Keith Batey. We put our heads together and in the calmer light of logic, and much ersatz coffee, solved the problem. Perhaps Welchman had a point when he said that ‘the work did not really need mathematics but mathematicians tended to be good at it’. Dilly made no objections to my having sought such help and even took it in his stride when, after a decent interval, I told him I was going to marry the ‘clever mathematician from Hut 6’. He gave us a lovely wedding present.

As our familiarity with the texts increased we could make charts of ‘clicks’ of key crib words, such as
Supermarina
; this covered not only ‘beetles’ but also ‘starfish’ where the text and hoped-for crib letter criss-crossed. The encoded message was written out vertically on squared paper and slid down the chart to locate clicks. To our delight we read a message dated 25 March 1941, which simply said ‘Today is X-3’ with a little top and tailing. Amazingly enough, in such a short telegraphic message they had used XALTX, which indicated a full stop, three times. We had a chart showing every possible position for this and an added bonus was that clicks might be found at appropriately staggered distances throughout the message. We were ‘exalted’ (Dilly’s quip) by the break and worked full out night and day to find what they were up to.

Each of the three days had a different setting, of course, and each message had to be broken separately. This was the Cottage triumph of the Battle of Matapan. When Cunningham came down to see us he was particularly anxious to see the actual encoded messages to his opposite number Admiral Iachino, on the strength of which he had made his battle plan. As a decoy he had been able to send his Force B to the actual rendezvous position, given in our message as 20 miles south of the island of Gaudo at 7 a.m., to intercept the Trieste division bent on attacking one of our convoys to Crete. Having effectively dealt with them, the Light Forces were to join Cunningham’s battle squadron from Alexandria to tackle the main Italian fleet where
Admiral Iachino was on the newly built
Vittorio Veneto
flagship. Cunningham was quite proud of his own secret service tactics and told us the now famous story of how he had gone ashore on the evening of X-1 [X minus 1] with a suitcase, as if intending an overnight stay, and spent some time on the golf course in Alexandria making sure that he was within sight of the Japanese consul, who was certain to report on his movements. Under cover of darkness he had slipped back to his flagship
Warspite
and the fleet sailed silently out of harbour. The consul must have been dumbfounded when he saw the harbour empty the next morning.

Dilly was ready with a poem to celebrate the occasion. Each verse began ‘When Cunningham won at Matapan by the grace of God and …’, mentioning all his girls with a rhyming tribute; the rhyme for Mavis conveniently being the flattering ‘rara avis’. All very heady stuff for a nineteen-year-old. Dilly was considered by some to see cryptography only as a theoretical problem unrelated to real events; but that was a mistake. Undoubtedly aerial reconnaissance played an important part in allowing Cunningham to draw up his battle plan, but it was Dilly who rang the Admiralty immediately to make sure that when the battle was reported in the press its success should be accredited entirely to reconnaissance to cover the real source. He chuckled in his poem when he referred to the reconnaissance ‘cottage aeroplane’. Clare as usual had organized shifts and kept our spirits up and so was given a special tribute.

Tribute was also paid to Margaret whose aim ‘straddled the target’ and, amongst others, to Hilda who ‘sank the
Vittorio Veneto
– or at least they can’t rebuild her’.

In 1974,
The Ultra Secret
by Frederick Winterbotham appeared with a picture of Bletchley Park on the front. All those who had kept the secret for thirty years were amazed. Could we now tell the family why we were so good at anagrams, Scrabble and crossword puzzles? But what was this ‘Ultra’ the jacket cover told us went on at Bletchley? We could never remember using the word. Dilly’s ‘girls’, some of them now grandmothers, eagerly looked in the index for some mention, but not a squeak about the Cottage, and Matapan was credited
to a
Luftwaffe
break in Hut 6, as Winterbotham had only known about air force intelligence. What about the rods and the drink with Cunningham? Maybe Dilly’s mentor, Lewis Carroll, had been right after all and life was but a dream.

Fortunately, it was the Italians who came to our rescue and proved it was real after all. The Germans had always accused the Italians of having traitors in their midst, which was made worse when, in 1966, H. Montgomery Hyde published the story of the beautiful spy, Cynthia, who had seduced Admiral Lais, the naval attaché in the Italian Embassy in Washington, and obtained the codebook from him which resulted in the Italian defeat at Matapan. As one reviewer observed, ‘treason in bed and death at sea made a libretto which sold well’, and the Admiral’s family felt obliged to take out a libel action, such a course being permitted in Italy on behalf of the dead. Montgomery Hyde was found guilty but the real evidence was not then available.

When
The Ultra Secret
was published, however, the Italians were delighted as it paid off an old score by proving that it was the Germans and not the Italians who were the culprits. They wanted to have Winterbotham’s book translated into Italian at once. However, Dr Giulio Divita, who was asked to edit the book, was determined to investigate the matter more fully and, when records were released in 1978, he found ample evidence that it was in fact decoded Italian and not German messages that had given the game away. The BBC ran its
Spy!
series in 1980 with an accompanying book, rehashing the Cynthia story of seduction and treason, now that it was official that breaking Italian ciphers had been responsible for Matapan; it was she after all who sent the codebooks to the Admiralty, which allowed the signals to be read. Dr Divita wrote to
The Times
about this misrepresentation of the facts, having by then decided to end the matter by tracking down the Bletchley Cynthia, or at least one of them. This wasn’t difficult as Ronald Lewin had already mentioned names in his book
Ultra Goes to War
, the first book about Bletchley since the release of official records.

I was able to scupper the idea that we had been given codebooks captured by Cynthia or anybody else; if we had had such books we shouldn’t have needed codebreakers as it would have been child’s play, given that we had a simulated machine. The Italian messages began with a five-figure number to which the operator referred in his list of keys and then inserted the wheels in the given order, adjusted the
clips on the side of them and put up the setting in the four windows as directed. Not having such a list, we had to break every message separately by Dilly’s rodding method as has been described. At last the Italians had got what they needed to exonerate poor Admiral Lais. They asked me if they brought the actual Matapan battle messages from Rome whether I would show them how they had been broken individually without a codebook. I warned them that as this all happened forty years ago there wasn’t much chance of my remembering the actual break.