Hut 3

The "German Army and Air Force Enigma Reporting Section" was set up in January 1940. That name, however, was soon dropped in favour of "Hut 3" as a description both of the location and of the functions and this was retained when, in February 1943 it moved into Block D. These became very much more than just the translation, interpretation and distribution of German Army and Air Force Enigma messages deciphered by Hut 6. By the time of D-Day in June 1944 Hut 3 was synthesising a torrent of signals intelligence ("SIGINT") data from multiple sources and producing an outgoing flood of useful intelligence.[5] David Kenyon, Research Historian at Bletchley Park has been able to access a number of unpublished sources, in particular "The History of Hut Three", a GCHQ document in The National Archives (HW3/119) for his 2019 book "Bletchley Park and D-Day: The Untold Story of How the Battle for Normandy Was Won".[6]

Initially, there were serious personal frictions between the four main people.[7] They were the original leader, Lieutenant-Commander Malcolm Saunders, Squadron Leader Robert Humphreys (senior liaison officer with the Air Force), Captain Curtis (senior liaison officer with the War Office, who knew no German), and Cambridge academic F. L. Lucas who had been in the Intelligence Corps in World War I.[8] Humphreys was “an excellent German linguist, but no team player”. He wanted to get his own way and found this difficult to do, if only because Saunders had a mind of his own. Nigel de Grey described the situation as "an imbroglio of conflicting jealousies, intrigues and differing opinions".[9]

Early in 1942 the Air Ministry sent Squadron Leader Eric Jones to investigate the problem. He had worked as a businessman in the textile industry for 20 years before joining up in 1940. His report so impressed the Director of GC&CS Edward Travis that, in July 1942, Saunders, Humphreys and Curtis were moved out of Hut 3, and Jones was promoted to Group Captain and put in sole charge.[10] Just over a year later, H. S. Marchant was made deputy to Jones, and the pair were in charge until the end of the war.[11] There were a number of sections: Air Section "3A", Military Section "3M", a small Naval Section "3N", a multi-service Research Section "3G" and a large liaison section "3L".[12]

The name “Hut 3” was retained when its functions and those of Hut 4, Hut 6, Hut 8 and the Signals Intelligence and Traffic Analysis group – known as "SIXTA" – moved to a new brick building, Block D, in February 1943.[13] The decoded messages from Hut 6 for Hut 3, which previously had been sent in a tray via a wooden tunnel between the huts, were then sent by a conveyor belt that “never stopped”.[14]

The Enigma “Red” cypher was the main cypher used by the Luftwaffe in every theatre where they operated. Red had been broken sporadically from the beginning of 1940, and from 22 May BP overcame some changes to the Enigma machines. From then on, Hut 6 broke Red daily to the end of the war, and it became the “constant staple” of ULTRA. Calvocoressi wrote that later in the war “we in Hut 3 would get a bit tetchy if Hut 6 had not broken Red by breakfast time.” [15]

Initially there were only four people in Hut 3, and there were serious personal frictions between them. They were the original leader, Lieutenant-Commander Malcolm Saunders, Squadron Leader Robert Humphreys (senior liaison officer with the Air Force), Captain Curtis (senior liaison officer with the War Office, who knew no German), and Cambridge academic F. L. Lucas who had been in the Intelligence Corps in World War I.[16] Humphreys was “an excellent German linguist, but no team player. He wanted to get his own way. He found this difficult to do if only because Saunders had a mind of his own. Nigel de Grey described the situation as 'an imbroglio of conflicting jealousies, intrigues and differing opinions'. Initially Travis moved the three [Saunders, Humphreys and Curtis] out of Hut 3 and put a small committee including Eric Jones in charge. As this did not work, Jones was made sole head in July 1942. Just over a year after he took over, H. S. Marchant was made his deputy, and the pair were in charge to the end of the war.” [17]

Army and Air Force Ultra was distributed by the SLUs (Special Liaison Units) set up by Frederick Winterbotham. By the end of the war there were about 40 SLUs to 40 commands. Signals were given a priority from Z to ZZZZZ (the highest of 5), and about 100,000 signals were sent to commands during the war [18]

The rules of interpretation for Hut 3 were that if the text was not explicit the Hut 3 officer could not add his interpretation without qualification; for a 1944 SS Panzer message where the placename had been missed or corrupted when received, the officer did not say simply “Dreux” but would say “slight indications Dreux” or “fair indications Dreux” or “strong indications Dreux”.[19] They could also add glosses preceded by the word “Comment”.[20]

The Air Index had “hundreds of thousands” of cards about 5 by 9 inches; so important that they were photographed and stored in the underground stack of the Bodleian Library in Oxford in case they were destroyed by bombing. Run by “about two dozen girls” and a man who was a “strange genius”, it had cards for every individual, unit, place or equipment so that any previous reference to (say) Major So-and-So could be found. There were two card indexes, 3A & 3M.[21]

• Malcolm Saunders, the original head
• Eric Malcolm Jones, head from April 1943
• Herbert Stanley Marchant, deputy head from 1943 (later Ambassador to Cuba and Tunisia) [25]
• Peter Calvocoressi, head of the Air Section
• F. L. (Peter) Lucas, head of the Research Section from July 1942; head of the History Section, from June 1945
• Ralph Bennett, Major (later professor of history at Magdalene College Cambridge) [26]
• John Cairncross, KGB agent [27]
• Donald A. Camfield [28]
• Captain Curtis
• Robert Humphreys
• Brinley "Bryn" Newton-John from Wales, father of singer Olivia Newton-John
• Oscar Oeser, Wing Commander [29]
• Reginald (Gerry) Bragg, translator (Director of Birmingham Polytechnic 1971). https://bletchleypark.org.uk/roll-of-honour/1052
• John H. Plumb, moved to the Naval section, Hut 8; (later a historian) [30]

A photograph of the Officers of 3A in 1943 or 1944 names them as: Labertouche, Brooke, Faure, Newton-John, Haskins, Bragg, Ware, Squire, Calvocoressi, van Norden, Harrow, Myers, Pilley, Manners-Wood, Rose, Cullingham, Millward.[31]

• Briggs, Asa (2011), Secret Days: Code-breaking in Bletchley Park, Barnsley, England: Frontline Books, ISBN 978-1-84832-615-6
• Calvocoressi, Peter (1980), Top Secret Ultra, London: Cassell Ltd, ISBN 0-304-30546-4
• Kenyon, David, Bletchley Park and D-Day: The Untold Story of How the Battle for Normandy Was Won, Yale University Press, ISBN 978-0-300-24357-4 The information from this source cited in this article is often in turn cited from a document “The History of Hut Three” an unpublished GCHQ typescript that is in The National Archives (TNA) HW3/119.
• Nelson, Eric L. (September 2018), "The peripheral and central indexes at Bletchley Park during the Second World War", The Indexer, 36 (3): 95–101
• Smith, Michael (2007) [1998], Station X: The Codebreakers of Bletchley Park, Pan Grand Strategy Series (Pan Books ed.), London: Pan McMillan Ltd, ISBN 978-0-330-41929-1
• Welchman, Gordon (1997) [1982], The Hut Six story: Breaking the Enigma codes, Cleobury Mortimer, England: M&M Baldwin, ISBN 9780947712341 New edition updated with an addendum consisting of a 1986 paper written by Welchman that corrects his misapprehensions in the 1982 edition.