MI8 - WikiHQ

MI8, or Military Intelligence, Section 8 was a British Military Intelligence group responsible for signals intelligence and was created in 1914. It originally consisted of four sections: MI8(a), which dealt with wireless policy; MI8(b), based at the General Post Office, dealt with commercial and trade cables; MI8(c) dealt with the distribution of intelligence derived from censorship; and MI8(d), which liaised with the cable companies. During World War I MI8 officers were posted to the cable terminals at Poldhu Point and Mullion in Cornwall and Clifden in County Galway, continued until 1917 when the work was taken over by the Admiralty. In WW2, MI8 was responsible for the extensive War Office Y Group and briefly, for the Radio Security Service.

History

thumb|National HRO receiver, extensively used by the RSS

MI8 was the signals intelligence department of the War Office that ran a worldwide Y-stations network. Additionally, for an 18-month period, from late 1939 to mid 1941, it also ran the Radio Security Service, under the designation of MI8c, but this was quickly handed over to MI6. The remainder of this page relates only to this small organisation, with, regrettably, no information concerning the major role of MI8.

MI8c

The Radio Security Service evolved from the Illicit Wireless Intercept Organisation (IWIO), which was given the designation MI1g and run by Lt Col. J S Yule. From an office in Broadway, IWIO collaborated with Military Intelligence, Section 5 (MI5) and with the General Post Office (GPO) to set up and control a small network of Direction Finding (DF) and intercept stations, to locate illicit transmissions inside Britain.

thumb|For security reasons, at the start of WWII, personnel employed in the Radio Security Service had to be housed in Wormwood Scrubs Prison

At the start of the Second World War, Vernon Kell, the head of MI5, introduced a contingency plan to deal with the problem of illicit radio transmissions. A new body was created, the Radio Security Service (RSS), headed by Major J.P.G. Worlledge. Until 1927, Worlledge had commanded a Wireless Company in Palestine. His brief was to "intercept, locate and close down illicit wireless stations operated either by enemy agents in Great Britain or by other persons not being licensed to do so under Defence Regulations, 1939".

Working from cells at HM Prison Wormwood Scrubs, Worlledge selected Majors Sclater and Cole-Adams as his assistants, and E.W.B. Gill as his chief traffic analyst. Gill had been engaged in wireless interception in the First World War and decided that the best course of action would be to find the transmissions of the agent control stations in Germany. He recruited a research fellow from Oxford, Hugh Trevor-Roper, who was fluent in German. Working with them, at Wormwood Scrubs, was John Masterman, who ran MI5's Double Cross System. Masterman already had Agent SNOW, and Gill used his codes as the basis for decrypting incoming agent traffic.

RSS assigned the task of developing a comprehensive listening organisation to Ralph Mansfield, 4th Baron Sandhurst. Sandhurst was an enthusiastic amateur radio operator. He had served with the Royal Engineers Signal Service during the First World War and had been commissioned as a major in the Royal Corps of Signals in 1939. There, a staff of analysts and cryptographers began their duties.

MI6 takeover

RSS had in effect become the civilian counterpart of the military's "Y Service" intercept network. By mid-1941, up to 10,000 logs (message sheets) a day were being sent to Arkley, then forwarded to the code-breaking centre at Bletchley Park. In May 1941, RSS's success and the fact that some of its personnel had managed to decode some Abwehr cyphers ahead of Bletchley, caused control of the organisation to be transferred. There was brief conflict over who would control it. In the end, it became the communication and interception service of MI6. Previously, MI6 had possessed no such capability.