Key figures in UK Sigint: Conel Hugh O’Donel Alexander

“Conel Hugh O’Donel Alexander died in 1974 and although his obituaries rightly spoke in glowing terms of his chess achievements, the impact of his more secret work still cannot be fully revealed.”

GCHQ Official website — May 5 2017

Conel Hugh O’Donel Alexander

Conel Hugh O’Donel Alexander (19 April 1909 – 15 February 1974), was an Irish-born British cryptanalyst, chess player, and chess writer. He worked on the German Enigma machine at Bletchley Park during the Second World War, and was later the head of the cryptanalysis division at GCHQ for over 20 years. Follow us on Twitter: @INTEL_TODAY

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Mathematitian, Chess player and Cryptoanalyst

MI5’s Peter Wright, in his 1987 best-selling book Spycatcher: The Candid Autobiography of a Senior Intelligence Officer, wrote about Alexander’s assistance to MI5 in the ongoing Venona project, as well as other important mutual cooperation between the two organizations, which broke down previous barriers to progress.

“Any help is gratefully received in this department”, Alexander told Wright, and that proved the case from then on. Wright also lauded Alexander’s professionalism, and opined that the exceptional mental demands of his cryptanalytical career and chess hobby likely contributed to Alexander’s early death at age 64, despite his healthy lifestyle.

“The great mathematician G. H. Hardy described C. H. O’D. Alexander as the only genuine mathematician he knew who did not become a professional mathematician. Hardy recognised that Alexander’s failure to win a fellowship at the Cambridge Tripos exams was most likely due to his attention being absorbed by chess.

Conversely, Alexander’s fellow chess International Master Harry Golombek said of the two-time British Champion “the demands of his profession left him with comparatively little time for [chess] practice and study; otherwise he would certainly have been of true grandmaster class, and possibly even of world stature“. Above both chess and mathematics, Alexander prioritised leading the British Government effort on cryptanalysis.” [GCHQ]

Early life

Hugh Alexander was born into an Anglo-Irish family on 19 April 1909 in Cork, Ireland, the eldest child of Conel William Long Alexander, an engineering professor at University College, Cork (UCC), and Hilda Barbara Bennett.

His father died in 1920 (during the Irish War of Independence), and the family moved to Birmingham in England where he attended King Edward’s School. He won a scholarship to study mathematics at King’s College, Cambridge, in 1928, graduating in 1931. He represented Cambridge in chess.

From 1932, he taught mathematics in Winchester, and married Enid Constance Crichton Neate (1900–1982) on 22 December 1934. Their elder son was Sir Michael O’Donel Bjarne Alexander (1936–2002), a diplomat. His other son was Patrick Macgillicuddy Alexander (20 March 1940 – 21 September 2005), a poet who settled in Australia in 1960. In 1938 Hugh Alexander left teaching and became head of research at the John Lewis Partnership.

Bletchley Park

In February 1940 Alexander arrived at Bletchley Park, the British codebreaking centre during the Second World War. He joined Hut 6, the section tasked with breaking German Army and Air Force Enigma messages.

In 1941, he transferred to Hut 8, the corresponding hut working on Naval Enigma. He became deputy head of Hut 8 under Alan Turing. Alexander was more involved with the day-to-day operations of the hut than Turing, and, while Turing was visiting the United States, Alexander formally became the head of Hut 8 around November 1942.

Other senior colleagues included Stuart Milner-Barry, Gordon Welchman, and Harry Golombek. In October 1944, Alexander was transferred to work on the Japanese JN-25 code.

Alexander was an early recruit to Bletchley Park; he began in Hut 6 working on Army and Luftwaffe Enigma messages before moving in 1941 to Hut 8 to join Alan Turing’s work on the Naval Enigma. Alexander had one of the most agile minds of the new breed of mathematical cryptanalysts; he proved the best at the pen and paper methods of ‘banburismus’ that reduced the computational work of Enigma attacks and his military aptitude test assessed him as suitable for development up to four star general. Although he has not achieved the renown of Good, Turing, Tutte, and Welchman, he was responsible for many breakthroughs.

Perhaps the most significant was spearheading the UK-US joint work breaking the Japanese CORAL system used by Naval attaches. More importantly, as a former teacher and head of research at John Lewis, Alexander was much better suited to the organisational and administrative tasks of Hut 8 than the hyper-rational Turing. Alexander gradually assumed more and more of this work. The story goes that one day when Turing arrived late at the Park and the record book asked him to name the head of his section; Turing wrote “Mr Alexander” and with the logic of bureaucracy Alexander was treated as the head of Hut 8 from then onwards. Praise for Alexander’s leadership is a theme common to all those who worked in Hut 8.


In mid-1946, Alexander joined GCHQ (under the control of the Foreign Office), which was the post-war successor organisation to the Government Code and Cypher School (GC&CS) at Bletchley Park. By 1949, he had been promoted to the head of “Section H” (cryptanalysis), a post he retained until his retirement in 1971.

“After the war, Alexander briefly returned to John Lewis before returning to the new GCHQ and continued to excel as both a cryptanalyst and leader. By 1949 he had been appointed head of the cryptanalysis division. It was a post that he held until his retirement, despite offers of promotion to more senior positions.

He used the weight of his position to testify strongly as a character witness on behalf of Alan Turing during Turing’s indecency trial. By 1971, already past the age of retirement by two years, Alexander decided to step down. Both GCHQ and their partners were keen to make continued use of his expertise and offered all manner of consultative work, which he declined.”

Chess career

He represented Cambridge University in the Varsity chess matches of 1929, 1930, 1931 and 1932 (he studied at King’s College, Cambridge). He was twice a winner of the British Chess Championship, in 1938 and 1956.

He represented England in the Chess Olympiad six times, in 1933, 1935, 1937, 1939, 1954 and 1958. At the 1939 Olympiad in Buenos Aires, Argentina, Alexander had to leave part-way through the event, along with the rest of the English team, because of the declaration of World War II, since he was required at home for codebreaking duties.

He was also the non-playing captain of England from 1964 to 1970. He was awarded the International Master title in 1950 and the International Master for Correspondence Chess title in 1970. He won Hastings 1946/47 with the score 7½/9, a point ahead of Savielly Tartakower.

His best tournament result may have been first equal (with David Bronstein) at Hastings 1953/54, where he went undefeated and beat Soviet grandmasters David Bronstein and Alexander Tolush in individual games. Alexander’s opportunities to appear abroad were limited as he was not allowed to play chess in the Soviet bloc because of his secret work in cryptography. He was also the chess columnist of The Sunday Times in the 1960s and 1970s.

Many knowledgeable chess people believe that Alexander had Grandmaster potential, had he been able to develop his chess abilities further. Many top players peak in their late twenties and early thirties, but for Alexander this stretch coincided with World War II, when high-level competitive opportunities were unavailable.

After this, his professional responsibilities as a senior cryptanalyst limited his top-class appearances. He defeated Mikhail Botvinnik in one game of a team radio match against the Soviet Union in 1946, at a time when Botvinnik was probably the world’s top player. Alexander made important theoretical contributions to the Dutch Defence and Petroff Defence.

White “Alexander, Conel Hughes” — Black “Botvinnik, Mikhail” [ECO “C18”] Result “1-0″[Radio]

In 1946, Alexander managed to win a game against Soviet Grand Master Mikhail Botvinnik, who was arguably the top player at the time. Botvinnik became the sixth World Champion in 1948. Botvinnik then held the title, with two brief interruptions, for the next fifteen years, during which he played seven world championship matches.[Wikipedia]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. Qg4 cxd4 8.
Qxg7 Rg8 9. Qxh7 Qa5 10. Rb1 Qxc3+ 11. Bd2 Qc7 12. f4 Nbc6 13. Nf3 Bd7 14. Ng5
Rxg5 15. fxg5 O-O-O 16. Qxf7 Qxe5+ 17. Kd1 Nf5 18. g6 Ne3+ 19. Kc1 Qe4 20. Bd3
Qxg2 21. Re1 Ne5 22. Qf4 Nf3 23. Re2 Qh3 24. Bxe3 e5 25. Qf7 dxe3 26. g7 Qg4
27. h3 Qg1+ 28. Kb2 Qg3 29. Bg6 Nd4 30. g8=Q Rxg8 31. Qxg8+ Kc7 32. Qh7 Kd6 33.
Bd3 e4 34. Qh6+ Kc7 35. Rxe3 Qe5 36. Ka2 Nf5 37. Qg5 Be6 38. Be2 d4+ 39. Reb3
b5 40. Qd2 d3 41. Bg4 1-0

Botvinnik just played 22. … Nf3 ??

While replaying the game, I discovered that Botvinnik had horribly blundered at move 22. Amazingly,  Alexander missed the opportunity to end the game right then! Alexander played 23. Re2 which is a good move, but certainly not the best. Actually, 23. Ba5 is devastating and Black has no choice but to resign on the spot.

This mistake does not seem to have been noticed until now. [The Radio Match Great Britain – URSS (1946)]  For the chess players among you, Komodo 8 rates 23. Ba5 at + 8.3 and 23. Re2 at +3.3; Houdini (4X64A) rates the moves at +13.4 and +3.9 respectively. Finally Deep Fritz (14 X64) rates these moves  at +9.2 and +2.2.

The reason is obvious. The threat of Qc7 (Checkmate)  is very powerful. And the natural response — Black pawn c6 — fails because of Bishop a6 — Checkmate. The only answer would have been 23. … e5. And then 24. Qf6 leaves the Black without a fighting chance. Even a genius can have a bad day.

In popular culture

Alexander appears as a supporting character in the 2014 film The Imitation Game, portrayed by actor Matthew Goode.

Synopsis: In THE IMITATION GAME, Benedict Cumberbatch stars as Alan Turing, the genius British mathematician, logician, cryptologist and computer scientist who led the charge to crack the German Enigma Code that helped the Allies win WWII.

Turing went on to assist with the development of computers at the University of Manchester after the war, but was prosecuted by the UK government in 1952 for homosexual acts which the country deemed illegal.


Conel Hugh O’Donel Alexander vs Mikhail Botvinnik —
URS-BCF (1946)

French Defense: Winawer. Poisoned Pawn Variation General (C18)·  1-0


Key figures in UK Sigint: Conel Hugh O’Donel Alexander — GCHQ Official website

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