Normally an obituary in The Times provides a framework for a biography, but that is not true of the eulogy of Mr Alfred Dillwyn Knox, CMG, fellow of King’s College and ‘a classical scholar and editor’, who died on 27 February 1943. Truly, as stated, he was a son of Bishop Knox of Manchester and brother of Mr E. V. Knox, editor of Punch, and of the Catholic theologian Monsignor Ronald Knox, and during the First World War he was a lieutenant in the Royal Naval Volunteer Reserve in the Admiralty. It also credits him for the erudition required to piece together the fragments of the Herodas Mimiambi and describes him as ‘a pioneer in a particularly difficult field’; but no mention could be made of his pioneering work in another even more enigmatic field, for which he had just received his CMG ‘for services to his country’ on his deathbed.
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.