The Y Service 1939-1945 
Bletchley Park sections
This document may be useful when read in conjunction with the Bletchley Park Roll of Honour.
The organisation at Bletchley Park was made up of a number of sections. The table below gives brief details of some of these.
| Name | Details |
|---|---|
| Air Section | Non-Enigma enemy codes and ciphers. There was also a sub-section of Hut 3, referred to as the Hut 3 Air Section or Air Intelligence Section, producing intelligence from Luftwaffe Enigma signals. |
| Cover, Traffic and Records (CTR), later CoverManagement Y (CMY) | Controlled Y service interception of diplomatic and commercial wireless networks |
| Central Signal Registry(CSR) | Subsection of Communications Section, handled all incoming and outgoing signal traffic. |
Distribution and Reference |
Mechanism for distributing intelligence reporting. |
| Intelligence Exchange (IE) | Formed in 1941 to replace Distribution and Reference for intelligence reporting on naval, army andair force matters. |
| Hut 3 German Army and Air Force Enigma Reporting Section. | Produced intelligence reports from signals deciphered by Hut 6. This section continued to be referred to as “Hut 3” after moving to Block D inFebruary 1943. |
| Hut 4 | See Naval Section. |
| Hut 6 | Location of German Army and Air Force Enigma Processing and Decryption Section. This section continued to be referred to as “Hut 6” after moving to Block D in February 1943. |
| Hut 8 | Location of German Navy Enigma Processing and Decryption Section from February 1940. This section continued to be referred to as “Hut 8” after moving to Block D in February 1943. |
| Illicit Signals Knox (ISK) | Deciphering of Abwehr (German Intelligence Service) Enigma coded signals. Initially headed by Dilly Knox. |
| Illicit Signals Oliver Strachey (ISOS) | Deciphering of Abwehr (German Intelligence Service) manually coded signals. Initially headed byOliver Strachey. |
| Inter-Service Special Intelligence School ISSIS) | Training school in Bedford for cryptographers, from 1941. Also provided Japanese language courses from 1942. |
| JAFO Japanese Forces. | Team formed in 1944 to work on Japanese army and air targets. Military Section Later Military Wing. |
| Naval Section | Sometimes referred to as “Hut 4”. Responsible for intelligence from naval Enigma messages deciphered in Hut 8 and also for deciphering and exploiting non-Enigma naval ciphers. Located in Hut 4 from 1940 to mid 1942, then in Blocks A and B. |
| No 4 Intelligence School(4 IS or IV IS) | Cover name given by the War Office to the Military Section or Wing of BP. |
| SIXTA | Responsible for Traffic analysis - the study of communications links, call-signs, frequencies and timings and lengths of transmissions, to build up a picture of the enemy's organisation, routine and dispositions. Name formed from No 6 Intelligence School and Traffic Analysis. |
| Wireless Telegraphy Coordination (WTC) | Controlled Y Service cover of enemy, naval and air force wireless networks |
Return To Index