Stuart Milner-Barry

Mavis Batey

Stuart Milner-Barry, the second youngest of six children (five sons and one daughter) of Edward Milner-Barry and Edith Besant, was born in Hendon on 20th September, 1906. His father was a professor of modern languages at the University of Bangor and his mother was the daughter of Dr William Henry Besant, a renowned mathematical fellow of St John's College, Cambridge University. (1)

Milner-Barry was educated at Cheltenham College and Trinity College, where he obtained firsts in the classical tripos (part I) and the moral sciences tripos (part I). After leaving university he became a stockbroker. He was devoted to chess and along with his friend, Hugh Alexander, played for England in 1937 and the following year became the chess correspondent of The Times. (2)

Government Code and Cypher School

After the outbreak of the Second World War he was recruited by his friend, Gordon Welchman, to join the Government Code and Cypher School (GCCS) based at Bletchley Park. Alastair Denniston, the head of the GCCS, was employing people to break the code used by the Enigma Machine. Denniston realised that in order to deal effectively with the increasing amount of secretly coded messages he had to recruit a number of academics to help with the work of the Government Code and Cypher School.

One of Denniston's colleagues, Josh Cooper, told Michael Smith, the author of Station X: The Codebreakers of Bletchley Park (1998): "He (Denniston) dined at several high tables in Oxford and Cambridge and came home with promises from a number of dons to attend a territorial training course. It would be hard to exaggerate the importance of this course for the future development of GCCS. Not only had Denniston brought in scholars of the humanities of the type of many of his own permanent staff, but he had also invited mathematicians of a somewhat different type who were especially attracted by the Enigma problem." (3)

As Peter Calvocoressi, the author of Top Secret Ultra (2001) has pointed out: "Over the years the Germans progressively altered and complicated the machine and kept everything about it more and more secret. The basic alterations from the commercial to the secret military model were completed by 1930/31 but further operating procedures continued to be introduced." (4)

Stuart Milner-Barry in Hut 6

Stuart Milner-Barry joined Gordon Welchman in Hut 6, which was responsible for breaking the German army and air force Enigma, at Bletchley Park. Stuart Milner-Barry told Mavis Batey, the author of Dilly: The Man Who Broke Enigmas (2009): "The codebreakers consisted of... a few old-time professionals who had worked in Room 40 at the Admiralty. Such for example as Dillwyn Knox, a Fellow of King's who died during the war... and new recruits such as Welchman and Alan Turing. Knox had so, I understand, been defeated by the Enigma, and the main credit for solving the Enigma and subsequently exploiting its success should (subject to the Poles) probably go to the other two." (5)

Lodgings had to be found for the cryptographers in the town. Stuart Milner-Barry was installed with Hugh Alexander at the Shoulder of Mutton Inn, in Bletchley. Milner-Barry later recalled: "Hugh and I were most comfortably looked after by an amiable landlady, Mrs Bowden. As an innkeeper, she did not seem to be unduly burdened by rationing, and we were able (among other privileges) to invite selected colleagues to supper on Sunday nights, which was a great boon." (6)

According to his biographer, Ralph Erskine: "Despite his powerful intellect, Milner-Barry always claimed modestly that he was not clever enough to be a cryptanalyst: he described himself as almost innumerate, but breaking Enigma tended to require a mathematical brain. Initially he helped to find ‘cribs’ (the probable plain text of messages enciphered on Enigma), without which it was almost impossible to break Enigma keys quickly. Hut 6 ‘menus’ (a form of program) for the ‘bombes’ (ultra-fast key-finding aids) depended entirely on accurate cribs. A single misplaced letter would almost certainly render a bombe run abortive, delaying the supply of vital intelligence." (7)

Funding at GCCS

Commander Edward W. Travis replaced Alastair Denniston as head of GCCS in February, 1941. (4) Later that year, Stuart Milner-Barry, Hugh Alexander, Alan Turing and Gordon Welchman wrote a letter to Winston Churchill concerning the funding of GCCS: "Some weeks ago you paid us the honour of a visit, and we believe that you regard our work as important. You will have seen that, thanks largely to the energy and foresight of Commander Travis, we have been well supplied with the 'bombes' for the breaking of the German Enigma codes. We think, however, that you ought to know that this work is being held up, and in some cases is not being done at all, principally because we cannot get sufficient staff to deal with it. Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention."

The men added: "We have written this letter entirely on our own initiative. We do not know who or what is responsible for our difficulties, and most emphatically we do not want to be taken as criticising Commander Travis who has all along done his utmost to help us in every possible way. But if we are to do our job as well as it could and should be done it is absolutely vital that our wants, small as they are, should be promptly attended to. We have felt that we should be failing in our duty if we did not draw your attention to the facts and to the effects which they are having and must continue to have on our work, unless immediate action is taken." (8) Churchill told his principal staff officer, General Hastings Ismay: "Make sure they have all they want on extreme priority and report to me that this has been done." (9)

Hugh Alexander
Hugh Alexander and Stuart Milner-Barry playing chess

By September 1943, when Milner-Barry was promoted head of Hut 6, it comprised about 450 staff. It has been claimed that his Hut 6 reports were models of clarity and good sense, while his invaluable organizational skills helped Hut 6 to cope with a wide range of new problems in 1944, caused by the Germans making several changes to the Enigma Machine. "Although he increasingly felt that Hut 6 was on the verge of losing the ability to decode Enigma, it held on until the end of the war, and this was due in no small part to his gifted leadership." (10)

In 1947 Milner-Barry married Thelma Tennant Wells. They had one son and two daughters. After the war he joined the Treasury. He made good progress and was appointed an assistant secretary in 1947 and promoted to under-secretary in 1954. In 1966 he became the ceremonial officer in the Civil Service Department, with responsibility for administering the honours system.

Sir Stuart Milner-Barry died on 25th March 1995 in Lewisham Hospital, London.

Primary Sources

(1) Gordon Welchman, The Hut Six (1982)

Recruiting for Hut 6 went fast. Travis produced a scientist, John Colman, to take charge of the Intercept Control Room, which was to maintain close contact with the intercept stations. Colman was soon joined by another scientist, George Crawford, a former schoolmate of mine at Marlborough College. Travis also persuaded London banks to send us some of their brightest young men to handle the continuous interchange of information with intercept stations. Thus, very soon, we had an intercept control team large enough to operate round the clock. They quickly established close and very friendly relations with the duty officers at Chatham.

For my part, I quite shamelessly recruited friends and former students. Stuart Milner-Barry had been in my year at Trinity College, Cambridge, studying classics while I studied mathematics. He was not enjoying being a stockbroker, and was persuaded to join me at Bletchley Park. He arrived around January 1940, when the Hut 6 organization was about thirty strong, bringing with him the largest pipes I have ever seen smoked. Stuart in turn recruited his friend, Hugh Alexander, who had been a mathematician at Kings College, Cambridge, and was then Director of Research in the John Lewis Partnership, a large group of department stores. They brought us unusual distinction in chess: Alexander was the British Chess Champion, while Milner-Barry had often played for England and was chess correspondent for the London Times.

(2) Stuart Milner-Barry, quoted by Mavis Batey, the author of Dilly: The Man Who Broke Enigmas (2009)

The codebreakers consisted of... a few old-time professionals who had worked in Room 40 at the Admiralty. Such for example as Dillwyn Knox, a Fellow of King's who died during the war... and new recruits such as Welchman and Alan Turing. Knox had so, I understand, been defeated by the Enigma, and the main credit for solving the Enigma and subsequently exploiting its success should (subject to the Poles) probably go to the other two.

(3) The Daily Telegraph (2nd September, 2010)

Keith Batey, who died on August 28 aged 91, was one of the leading codebreakers working on the German Enigma machine ciphers at Bletchley Park during the Second World War.

Batey was among the first mathematicians to be recruited to work in Hut 6, the section of the Government Code and Cipher School which broke German army and air force Enigma messages. He later moved to the ISK section, which broke the Enigma messages of the Abwehr, the German military intelligence service.

The initials ISK stood for Illicit Services (Knox) – after Alfred 'Dilly' Knox, the brilliant codebreaker who had broken the Abwehr Enigma before dying of stomach cancer in 1943. ISK became operational early in 1942 and finally expanded into a staff of more than 100. Four European Abwehr networks were targeted by ISK: two in the West and two in the East.

Batey himself was responsible for some important breakthroughs in decrypting the Abwehr Enigma system, helping MI5 to control the entire German espionage network in Britain. The intelligence was crucial to the Double Cross system – under which MI5 turned German agents sent to Britain and used them to feed the Abwehr false information – as it showed that the information was being accepted as genuine; it further revealed what the Germans did and did not know about the D-Day invasion plans.

The Allies were able to use the double agents to "reveal" to the Germans the presence of a bogus US army group stationed in East Anglia and south-east England that was to land in the Pas-de-Calais. As a result, Hitler kept two German divisions that had been destined for Normandy in the Calais area.

John Keith Batey was born at Longmoor, Cumberland, on July 4 1919. His father, John, had been invalided home from the Somme; Keith's mother, Elsie, had to support the family on her wages as a part-time teacher.

Keith was educated at Carlisle Grammar School, from where he won a state scholarship to read Mathematics at Trinity College, Cambridge.

Another scholar at Trinity, Gordon Welchman, had been recruited to work for the Code and Cipher School, which had moved to Bletchley Park on the outbreak of war. Welchman was one of the brightest of a number of mathematicians recruited by the head of Bletchley Park, Alastair Denniston – a policy that initially horrified the classics scholars (like Knox) who then dominated codebreaking.

Selected to lead a new team working on German army and Luftwaffe Enigma machine ciphers, Welchman returned to Cambridge in June 1940 to recruit more mathematicians; among them was Batey.

While he relished the intellectual challenge of working in Hut 6, Batey felt guilty that, while so many of his contemporaries were fighting, he was reserved for what he saw as a "cushy" job. In 1942 he decided that he wished to play a more active part in the war.

Accordingly he told his bosses that he wanted to train as a pilot, only to be informed that no one who knew that the British were breaking Enigma could be allowed to fly in the RAF, the risk being that he might be shot down and captured.

Batey then suggested that he join the Fleet Air Arm, flying over the sea in defence of British ships, arguing that he would be either killed or picked up by his own side. Worn down by his persistence, his superiors reluctantly agreed.
On his solo flight during training, Batey came in to land so low that the examiners had to dive to the ground to avoid decapitation. None the less, he passed – probably because of the desperate need for new pilots.

Batey was due to go to Canada for the Fleet Air Arm advanced flying course in late 1942, by which time he was engaged to Mavis Lever, a young female codebreaker who was working with Knox. Batey and Mavis had met when he helped her to solve a complex cipher problem. Mavis later recalled: "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 said 'clever mathematician from Hut 6'. He gave us a lovely wedding present."

The couple married in November 1942, shortly before Batey left for North America. Batey's Fleet Air Arm career never progressed any further. He was seen as being more valuable at Bletchley than flying naval aircraft, and was ordered back from Canada to work in a new section working on the Abwehr Enigma.

Knox, having made the initial breakthrough into the machine which was used for high level communications between the Abwehr in Hamburg and their stations in occupied Europe, was now terminally ill. Batey, working alongside his new wife, enjoyed a number of successes of his own. In August 1943 he solved the Enigma ciphers of the Sicherheitsdienst, the Nazi party's own intelligence service. Three months later he cracked the cipher used by the Spanish military attachés in Berlin and Rome to report back to Madrid on German and Italian military plans and assessments.

He would subsequently go on to write much of the official history of the ISK section, which has still not been released by GCHQ.

Batey had a formidable intellect which could alarm some of Bletchley's less exalted staff. In her biography of Dilly Knox, Mavis Batey recalls: "[Keith] tried to give a newcomer a tutorial on how the machine worked technically and afterwards she fled, never to be seen again; it was rumoured she had a nervous breakdown."

After the war Batey passed the Foreign Office examination. He served in the high commissioner's office in Ottawa from 1947 to 1951 and then as private secretary to Philip Noel-Baker, Secretary of State for Commonwealth Relations.

He was transferred to several other Civil Service departments, one of which involved dealing with guided weapons, and in 1955 was appointed Secretary of the Royal Aircraft Establishment at Farnborough, working there for 12 years.
In 1967 Batey spotted an advertisement for the post of Secretary of the Chest at Oxford, the university's financial officer. He got the job, and five years later was invited to become Treasurer of Christ Church.

On his retirement in 1985, he was presented with bookshelves made from the original timber of the frame of Great Tom, the bell in Tom Tower, which sits over the main gate to Christ Church and was designed by Sir Christopher Wren.

He was recently asked to contribute to a forthcoming history of his alma mater, Portrait of Trinity – an enterprise to counter the damage done to the college's image by its having produced four members of the so-called Cambridge spy ring (Kim Philby, Guy Burgess, Anthony Blunt and John Cairncross).

Batey was able to reassure the college that it had also made a positive contribution to British intelligence operations, with five of the leading codebreakers – Welchman, Stuart Milner-Barry, Bill Tutte, Rolf Noskwith as well as Batey himself all having been recruited while at Trinity.

Batey retained his faculties to the end. Given the standard compos mentis test by his doctor shortly before his death, he answered every question correctly and then said: "Now, young man, what do you know about Fourier analysis?" before proceeding to give the startled doctor a lecture on the subject.

Keith Batey is survived by his wife and by a son and two daughters.

Student Activities

Alan Turing - School Student (Answer Commentary)


(1) Ralph Erskine, Oxford Dictionary of National Biography (2004-2014)

(2) Gordon Welchman, The Hut Six (1982) page 84

(3) Michael Smith, Station X: The Codebreakers of Bletchley Park (1998) page 16

(4) Peter Calvocoressi, Top Secret Ultra (1980) page 31

(5) Stuart Milner-Barry, quoted by Mavis Batey, the author of Dilly: The Man Who Broke Enigmas (2009) page 81

(6) Sinclair McKay, The Secret Life of Bletchley Park (2010) page 61

(7) Ralph Erskine, Oxford Dictionary of National Biography (2004-2014)

(8) Francis Harry Hinsley, Oxford Dictionary of National Biography (2004-2014)

(9) Hugh Alexander, Alan Turing, Gordon Welchman and Stuart Milner-Barry, letter to Winston Churchill (21st October, 1941)

(10) Ralph Erskine, Oxford Dictionary of National Biography (2004-2014)