Dilly

by Batey, Mavis;

  Those services were only revealed thirty years later when F. W. Winterbotham published the story of Bletchley Park in The ULTRA Secret. Dilly, as he was known to family, friends and close colleagues, was then first mentioned by name as ‘the mastermind’ behind the Enigma affair. Winterbotham added: ‘He was quite young, tall, with a rather gangling figure, unruly black hair, his eyes behind glasses, some miles away in thought. Like R. J. Mitchell, the designer of the Spitfire fighter aircraft, which tipped the scales in our favour during the Battle of Britain, who worked himself to death at the moment of triumph, Knox too, knowing he was a sick man, pushed himself to the utmost to overcome the problems of Enigma variations, which also helped to tip the war in our favour. He too died with his job completed.’

  His biography is long overdue. Like all those who worked for him at Bletchley Park and shared his Enigma successes, I have affectionate memories of a brilliant, humane, intuitive, if eccentric, genius with an unfailing sense of humour, loyalty and fair play.

  John Tiltman, the chief cryptographer, who collaborated with Dilly on many occasions in the 1930s, saw cryptography ‘as much closer to art than science, and that is what makes the personal factor so important’. This is particularly true of Dilly Knox and we are therefore fortunate to have first-hand accounts from his family, colleagues and friends of his early life, personality, motivation and talents, which were the making of a cryptographer.

  Chronology of events

  1884 23 July

  Alfred Dillwyn Knox born in Oxford.

  1884 Dilly’s father, Edmund Arbuthnott Knox, leaves Merton College to take up living at Kibworth in Leicestershire.

  1891 Father moves to Aston, Birmingham, as Bishop Sufragan of Coventry.

  1895 Dilly sent to Summer Fields preparatory school in Oxford.

  1896 First in election to Eton.

  1903 Father becomes Bishop of Manchester.

  1903 Dilly becomes a scholar at King’s College, Cambridge, reading classics. Heavily influenced by Walter Headlam.

  1907 Leaves Cambridge. Teaches classics and ancient history at St Paul’s.

  1909 Fellow of King’s College, Cambridge. Begins work on completing Headlam’s Herodas. Commutes from Cambridge to British Museum to work on papyri.

  1914 Outbreak of war. Tries to enlist as military dispatch rider but eyesight fails him.

  1915 Dilly joins Admiralty’s Room 40 codebreaking section.

  1917 Breaks U-boat code. Commissioned as lieutenant in the Royal Naval Volunteer Reserve.

  1919 Decides to continue as a codebreaker through peacetime in the newly formed Government Code & Cypher School (GC&CS).

  1920 Marries his Room 40 secretary Olive Roddam.

  1921 Moves to Courns Wood, near High Wycombe, Buckinghamshire.

  1922 GC&CS placed under Foreign Office. Dilly works on diplomatic messages.

  1922 Publishes the Headlam/Knox Herodas.

  1923 Offered professorship of Greek at Leeds University as result of dissertation on Cercidas and his work on Herodas.

  1923 Arthur Scherbius markets a new electro-mechanical cipher machine which he calls Enigma.

  1925 GC&CS moves to share offices with Secret Intelligence Service (SIS) at Broadway Buildings. Dilly said to acquire an Enigma in Vienna for his own use.

  1926 Dilly works with John Tiltman to break messages passed by clandestine network of Comintern agents. Codebreaking operation is codenamed Mask.

  1928 GC&CS acquires a commercial Enigma machine.

  1929 Dilly publishes new translation of Herodas for Loeb Classical Library edition.

  1929 Hugh Foss breaks commercial Enigma machine as part of GC&CS test of its security for possible use by British government. Deems it too insecure.

  1930 Germany adds plugboard to commercial machine, significantly enhancing its security. Dilly and Tiltman continue to concentrate on Comintern and Soviet codes and there is little interception of German messages.

  1931 Gustave Bertrand obtains German spy ‘pinches’ of material from a French agent inside the German war ministry codenamed Asché. Bertrand offers more documents but demands payment. Offer not taken up but photographs taken during assessment of material reveal the addition of the plugboard.

  1931 Offer of Bertrand’s Asché ‘pinches’, including daily army machine settings, eagerly accepted by Poles.

  1932 Polish codebreaker Marian Rejewski breaks the Enigma machine theoretically using permutation theory.

  1933 Poles begin reading German Enigma messages. Hitler comes to power and begins building up the German armed forces.

  1935 Mussolini’s Italy invades Abyssinia. Joint Anglo-French wireless intercept station set up in southern France.

  1936 Germany sells commercial Enigma machine to Italy and Spain. German plugboard Enigma messages intercepted when German navy carries out manoeuvres in the Mediterranean.

  1937 Dilly uses his own ‘rodding’ techniques to break the wiring on the wheels of the ‘K’ model commercial machine used by Italy in the Spanish Civil War. Wilfred Bodsworth, another GC&CS codebreaker, uses Dilly’s ‘rodding’ techniques to break the Enigma machine used by the Spanish naval attaché. Dilly turns his attention to breaking German army and air force messages through their indicators.

  1938 March Germany annexes Austria. Admiral Hugh Sinclair, the SIS Chief, buys Bletchley Park as a ‘war station’ for both SIS and GC&CS.

  August Codebreakers make practice visit to Bletchley under cover of ‘Captain Ridley’s Shooting Party’.

  November Bertrand is invited to meet codebreakers and hands over spy ‘pinches’, known here as ‘Scarlet Pimpernels.’ These include an operator’s manual which gives ninety letters of clear text and its enciphered equivalent together with the key setting. Dilly now only needs to know the diagonal, the order in which the machine’s typewriter keys are connected to the entry plate to break the German army and air force Enigma. The diagonal on the commercial machines followed the keyboard and so was called the QWERTZU by Dilly.

  1939 January Meeting between the British, Polish and French codebreakers in Paris produces nothing new for the British.

  1939 July Meeting in Pyry Forest just outside Warsaw tells Dilly what he needs to know. The diagonal was not QWERTZU as in the commercial machines but ABCDE, such a simple order that the British codebreakers had dismissed it without even testing it. Dilly sends the information back to GC&CS and the wheel wiring is broken within two hours. By now he has been diagnosed with lymphatic cancer.

  1939 August GC&CS moves to Bletchley Park ‘war station’. Dilly put in charge of research section in the Cottage, assisted by Tony Kendrick, John Jeffreys, Alan Turing, Peter Twinn, Gordon Welchman and three female clerks. Sets up workshop in the stable-yard, where engineers work with Turing on experimental electro-mechanical codebreaking, which leads to the creation of the bombe.

  1940 January First current German Enigma message broken in Cottage. Dilly invents ‘cillis’ to speed up codebreaking process and solves weather codes which give away daily plugboard settings. Success of Turing’s bombe turns Bletchley Park into a production line, leaving Dilly feeling sidelined. In March, he is given a new Enigma research section in the now enlarged Cottage and sets to work breaking the machines no one else can manage.

  1940 German railway Enigma broken by Hut 8 using Dilly’s methods. Turing’s Treatise on Enigma explains Dilly’s methodology to newcomers.

  1940 September Italian navy Enigma messages broken.

  1941 March Cottage breaks details of Italian navy plans for Battle of Matapan, leading to British success.

  1941 October Dilly breaks Abwehr multi-turnover ‘Lobster’ Enigma, allowing SIS to monitor German secret service messages. This is vital to the Double Cross system of captured German agents used by MI5 and SIS to feed false information to the German high command about allied intentions during the invasions of north Africa and Italy and most particularly for the D-Day Normandy landings.

  1942 Dilly’s team, now k
nown as Intelligence Services Knox (ISK), breaks the Abwehr GGG machine used for communications with Spain. Dilly is now so ill that he is only able to work from home. Twinn takes over temporarily as head of section, but Dilly is still very much at work behind the scenes.

  1943 27 February Dilly dies at home, aged fifty-eight, having been given the CMG on his deathbed by an emissary from the Palace. He sends the decoration to his ISK section, saying that it was really earned by them.

  ONE

  The making of a codebreaker

  The Knox family was a remarkable one by any standards. Alfred Dillwyn Knox, born on 23 July 1884, was the second of the four brilliant sons of Edmund Arbuthnott Knox, later Bishop of Manchester. Dilly and his elder brother Eddie were born in Oxford, where their father was sub-warden of Merton College, one of the oldest colleges. Merton was founded in 1264 as an independent academic community for training the secular priesthood. Ordained and elected as a fellow in 1870, the Rev. E. A. Knox’s reading was not entirely confined to theological works as he was fond of Jane Austen novels. In 1874, he met his future wife Ellen, the daughter of Thomas French, who was the new rector of St Ebbe’s Church, Oxford, opposite Christ Church. French had just returned from missionary work in India. According to Edmund’s diary, he and Ellen were allowed to walk in the garden on their own and had ‘a profitable talk in the summerhouse’. Thomas French approved of Edmund’s preaching at a church in a run-down Oxford parish. The young couple had to wait four years, however, before they could get married, when Merton amended its statutes to abolish the celibacy rule.

  Four children were born in Oxford, Ethel, Eddie, Winifred and Dilly, and with such a growing family, Edmund Knox was pleased, in 1885, to be offered the living of St Wilfred’s at Kibworth in Leicestershire, which was under the ecclesiastical patronage of Merton. This was no casual college appointment, as for him heredity and motivation related whole-heartedly to the evangelical Church of England. When the children came to make the family tree there was a clergyman to be found on every line of both parents’ genealogy, and they had been given a special ancestor to remember by the choice of one of their names. Dilly was named after his great-grandfather Peter Dillwyn French, vicar of Holy Trinity, Burton-on-Trent, the father of Thomas French, who had been ‘called’ back to India, this time as Bishop of Lahore.

  The rectory at Kibworth was a paradise for the boys and their sisters Ethel and Winifred. Their father also remembered it with great affection in his Reminiscences of an Octogenarian as ‘exactly the house that Jane Austen’s Mrs Elton would have approved of with its lofty hall and reception rooms – its bay windows looking out on the rectory garden and fields’. There were strawberries, raspberries and Victoria plums for the picking, a snug rookery and rook pies in season, aconites, primroses and violets in the shrubbery and, as Edmund Knox said, ‘like Herrick, our cows and a few sheep disporting themselves in our own field. What more could we wish?’ In later years, the children used to say that they could cure sleeplessness simply by recalling Kibworth. The large nursery was at the top of the house, and for much of the time there they were taught at home with their father providing religious instruction and their mother, who had had a very sound literary education, reading to them by the hour. Dilly and Eddie later went to the village school. The great excitement was when their grandfather visited them from Lahore and took them all for holidays, telling them about his amazing missionary adventures. Just when everybody thought he had retired, he decided to set off again, this time to convert the Arab world, and there, after incredible hardships, he died and was buried under the cliffs in a cove on the Bay of Muscat. The children invented a new hiding game called the Caves of Arabia in remembrance.

  Whether as missionaries or as clergymen, the Knoxes were brought up to pray for all relatives preaching the gospel at their family prayers. Soon their father, much as he enjoyed the rural parish of Kibworth and the family delights, knew he ought to be catering for the spiritual needs of industrial cities. Dilly was seven when, in 1891, they moved to their new life at Aston on the outskirts of Birmingham. Eddie and Dilly were now able to go to a day school, revelling in the trams that took them there. The vicarage was described by its new incumbent, who was concerned about his wife’s health, as ‘in a dark and narrow street set in a maze of smoke begrimed houses’, but she, like her unworldly father, felt that sacrifices had to be made and that she was ‘called’ to brighten the lives of the industrial poor. Ellen Knox threw herself whole-heartedly into reading classes for adults, Sunday schools and the Ragged School for destitute children. Sadly at Christmas, deep in her charitable work, she caught influenza. For the next eight months she was sent to one nursing home after the other ‘for the air’, but in August 1892 she died.

  The children were inconsolable, especially when they were separated. Only Eddie, who was then twelve, remained at Aston with his father. Dilly and the girls were sent to a widowed great-aunt in Eastbourne, and the younger boys, Wilfred and Ronnie, were packed off to their father’s brother, the vicar of another Leicestershire village, Edmondthorpe. Dilly was utterly miserable and soon learned all they could teach him at the Eastbourne school. The only consolation was the occasional reunion at Aston when Eddie and Dilly were particularly pleased to be together again. Aunt Emily, who was in charge of the Bishop’s household, had no ideas about what children needed and it was clear that family life could not be what it had been. In 1894, Edmund Knox was offered the vast parish of St Paul’s, Birmingham, with the post of Bishop Suffragan of Coventry, and in his own words ‘it became evident that I must marry again’, and that his wife must be vicarage born and bred to be able to cope with his situation. Fortunately, Ethel Mary Newton, aged twenty-seven, was ideal. The children were to call her ‘Mrs K’, she said, which would not usurp their mother’s memory, but they responded to her immediately. She wore Liberty gowns, introduced William Morris chintzes into the dark sitting rooms and called their father ‘Bip’, an affectionate shortening of ‘Bishop’. She was as literary minded as their mother had been and had taught herself Greek and Latin. The entry in her diary for the wedding day, cherished by the family, read: ‘Finished the Antigone. Married Bip.’

  We have a first-hand account of what it was like to take on Bip’s children in an article she was persuaded to write for the Daily Chronicle in 1930. When she first met them, she said, Eddie occupied the single shabby armchair, reading aloud with ribald comments Smiles’s Self Help. Dillwyn sat lost in a Greek lexicon, Wilfred manipulated a toy train, the girls played a duet on the piano. Ronnie lay before the fire with Wylde’s Natural History. They greeted her politely and continued with their pleasures. She withdrew and said to the Bishop: ‘They really are clever children. They can occupy themselves.’ Five minutes later, the scared face of Winifred appeared at the study door. ‘You must come up. The boys are murdering one another.’ She found the little boys cowering in corners; the furniture was overturned; Self Help had gone out of the window, and Eddie and Dillwyn were locked in what seemed a death grapple.

  Something had got to be done to tame them. Edmund Knox was not in favour of boarding schools at their age, but everyone was aware that there was no money for public school education and that they would have to get scholarships. Eddie first went to a preparatory school at Hemel Hempstead and won a scholarship to Rugby in 1896, and Dilly went to Summer Fields in north Oxford, where he only needed a year’s coaching to obtain his scholarship to Eton in 1897. Their step-mother organised the summer family reunions with great care. The location was discussed at Christmas and debated at Easter and every summer with their eight bicycles, golf clubs, book-boxes, fishing rods and tennis rackets they migrated for six weeks to some remote inexpensive house, usually a rectory. ‘Everyone seemed in any holiday either to be reading for an examination or a scholarship,’ Winifred remembered. For relaxation, the Bishop cheerfully spent hours playing cricket with the boys, Mrs K and the girls picking up the balls.

  The brothers’ reunions were eagerly ant
icipated at all stages in their lives and different careers. The shape of things to come began when Eddie, who would become a famous editor of Punch, produced a family magazine, Bolliday Bango, a parody of the popular weeklies of the day with gossip, news and jokes, in his school holidays. Ronnie, aged eight, wrote a Latin play for him, and Dilly, aged twelve, contributed a remarkably elaborate cipher. There was to have been a further instalment of Dilly’s contribution, but the editor would have none of it. Rules for games and activities were essential, but any one of them who had a birthday was entitled to make his own rules for the day. One of Dilly’s rules was ‘nothing is impossible’.

  In 1903, when Dilly was preparing to go up to King’s College, Cambridge, the family underwent a great change when their father became Bishop of Manchester, and they moved to Bishopscourt, where the boys now had their own study on the ground floor. Ronnie, the youngest, was a precocious fifteen and many and varied were their amusements, solving problems being a particular fascination. They wrote a letter to Sir Arthur Conan Doyle pointing out errors in the Sherlock Holmes stories, enclosing four dried orange pips, an allusion to the letter in The Sign of Four. They were disappointed that he did not reply, but he did write to Ronnie when he published his Studies in the Literature of Sherlock Holmes in 1912. The brothers were fascinated by the arguments surrounding the controversial claims that Shakespeare’s plays were in fact written by Francis Bacon, and Ronnie used Baconian reasoning to prove that Queen Victoria was the author of Tennyson’s ‘In Memoriam’.