Alastair Denniston

A fascinating biography of Alexander ('Alastair') Guthrie Davidson, 1881-1961, wheelhorse of British

  1. seaweed
    Joel Greenberg
    This is much more than a biography of Alexander ('Alastair') Guthrie Davidson ('AGD'), 1881-1961, wheelhorse of the British Signal Intelligence (SIGINT) effort at the start of Hitler's War. It is also the story of SIGINT itself from 1914 onwards. It starts with the WW1 story of Room 40 under 'Blinker' Hall, the Director of Naval Intelligence (DNI) with a fascinating focus on the Zimmerman Telegram - and more importantly how it was handled - so as to bring America, under its muddle-headed pacifist President, into the War. It was here that AGD, in 1914 luffed in from his post teaching French and German to RN cadets at Osborne, started as a night watchkeeper and learned what was to be his trade.

    The war over, AGD as the last man standing in Room 40 - and also clearly the most experienced man available - was put in charge of what was now the Government Code and Cypher School (GC&CS), reporting to Admiral 'Quex' Sinclair, Hall's successor as DNI. The focus was on diplomatic traffic and in 1922 GC&CS was transferred from the Admiralty to the Foreign Office, still under Sinclair and co-located in London with Quex's other baby, the Secret Intelligence Service (SIS aka MI6). The (somewhat surprising) list of countries whose traffic we were reading steadily grew, as, necessarily, did the number of staff, and with that the organisational headaches visited on AGD. As we rolled towards another war AGD's wartime OBE was upgraded to a CBE (and in 1941 supplemented by a CMG). In August 1939 GC&CS was moved to Bletchley Park where AGD had to soothe many prima donnas' ruffled feathers as he struggled to cope with the relocation and overcrowding, the last continually aggravated by rapid expansion.

    Unsupported from above, partly because the secret nature of the work could not be explained to all and sundry, disloyally undermined from below, hampered by ministerial and military turf wars, always short of physical resources, grossly overworked and it would seem overwhelmed by the management task, hampered I think by a gentlemanly reluctance to engage in politics, AGD was sidelined in February 1942, in spite of the tremendous success of ULTRA and the cracking of Enigma on AGD's watch. We leave the Bletchley story there as its operation went to AGD's victorious deputy and follow AGD and GC&CS' civil and diplomatic sections (still under his charge) to London. He and his operation continued to deliver applauded results which were reported as a model for similar US activity. Nevertheless the sharks were still circling and AGD was forced into retirement in December 1944. No knighthood, such as nowadays is given for kicking a child's ball about, for AGD: the reasons are discussed.

    The author, Joel Greenberg, is a mathematician who cut his literary teeth with his excellent 2014 biography of Gordon Welchman, Bletchley cryptanalyst. Here the subject, AGD, is instead, force majeure, more of an administrator. In the Kaiser's War it was linguists who were prominent; in Hitler's it was mathematicians (and others) who were needed as the enemy's codebooks had given way to electro-mechanical cryptography. We are, however reminded how in both wars other means such as direction finding and traffic analysis were also key to producing a complete intelligence picture. Someone had to herd the cats however and that someone was AGD.

    The family have fully cooperated, contributing some photographs which show AGD as a family man, although he appears (rightly) not to have discussed his work much en famille. As to the presentation, the final fifth consists of appendices giving detail for some of the matters discussed in the main text. There is the usual infuriator of asides remitted to the notes of which one nevertheless has to keep track in order best to follow the story. There is an extensive bibliography; curiously William Clarke is credited with a work by Arthur Marder.

    The result is a thoroughly readable and very interesting book and a valuable addition to the historiography of secret intelligence 1914-45, cryptography and cryptanalysis, Room 40, Bletchley Park and so forth.