The Radio Security Service (R.S.S.) was formed as part of the Security Service, also known as M.I.5. until being transferred to the Secret Service Intelligence, or M.I.6. in May 1941. The aim of the R.S.S. was to intercept radio signals produced by German spies and the German intelligence service, the Abwehr. A number of radio interception stations were built across Britain, with large aerial arrays and several huts.
In addition to such installations, the R.S.S. operated a large number of Voluntary Intercepts (VIs), part-time radio operators who would carry out the same function of monitoring radio frequencies for any unexpected transmissions, but operated using radio sets in their own homes. Any intercepted messages were forwarded to P.O. Box 25, Barnet, which was a cover address for the organisation. To provide additional cover, Volunteer Intercepts were issued with Royal Observer Corps uniform.
Despite such measures, the secrecy surrounding the R.S.S. was breached when an article on the work of the organisation appeared in the Daily Mirror on 14 February 1941. This article noted that "Britain's radio spies are at work every night...Home from work, a quick meal, and the hush-hush men unlock the door of a room usually at the top of the house. There, until the small hours, they sit, head-phones on ears, taking down the Morse code messages which fill the air."
Two East Lothian men were members of the Radio Security Service. Mr. Amos of Haddington and Mr. Coventry of North Berwick both carried out radio monitoring work. Mr William Amos carried out his work on equipment set up in the rear of his electrical shop in Market Street, Haddington, and both he and his shop assistant. Lizzie Tully-Jackson, had to sign the Official Secrets Act. Mr. Amos received the British Empire Medal in January 1946 in recognition of his services. However, the entry in The London Gazette notes that the award was to "William Alexander Amos, Observer, Royal Observer Corps," highlighting the fact that the real reason he received his award could not be outlined and mention could only be made of the cover organisation to which Voluntary Intercepts were ostensibly attached.
Voluntary Interceptors were recruited largely from the ranks of the Radio Society of Great Britain because they already had the necessary short wave radio receivers to pickup transmissions. The transmitters used by the radio amateurs before the war had, however, been impounded at the outbreak of war for security reasons. The initial tasks of the VIs were to detect transmission from German spies operating in Britain and locate their position. The VIs were given the authority to enter property from which they suspected illegal radio signals were being transmitted. It is now known that all German spies in Britain during the war were captured and either executed or 'turned' to become double agents, sending false information back to the Germans. This only became certain after the war, but the VIs discovered a lack of covert transmissions from within Britain, which suggested there were no German spies at large.
Despite this, there is an unconfirmed report of unauthorised transmissions being sent from East Lothian. A radio engineer was woken in the night and taken by Military Police into the Lammermuir hills where there was a number of soldiers with a civilian under arrest. The engineer was ordered by an Army officer to inspect a radio transmitter. When asked if it was capable of transmitting to Germany, the engineer answered yes. The soldiers then took the civilian away and there was a volley of shots in the darkness. The soldiers returned, and left again with shovels, a sound of digging being audible. The officer then instructed the engineer to forget what happened that night and never to talk about it, and he was taken back to his home. Although it has not been possible to find further evidence of this incident, it would appear that either Mr Amos or Mr Coventry may have been monitoring the transmissions of this German agent for some time.
Despite this incident, because of the lack of transmissions from spies, the Voluntary Interceptors were instead each instructed to monitor a specific section of the short wave band for faint signals which did not fit normal patterns of commercial or military traffic. By listening to the same small range of frequencies, the VIs would become accustomed to the regular signals and would therefore be able to pick up on the occasional, faint transmissions which were of interest. As well as details of the Morse code message, the call sign of the station, time of transmission, signal strength, etc., were all noted. Such details were collated in Barnet, where all the messages were sent, and it was often possible to identify stations even though they had changed their call signs.
The largest group of signals monitored by the Voluntary Interceptors was Group 2, which was military intelligence based in Berlin. Such signals were frequently encoded on the Enigma enciphering machine and although the VIs would note the contents of the message in Morse code, they could not, of course, decipher it and read its meaning. For this, the messages were sent from Barnet to Bletchley Park, the location of the Government Code and Cipher School, where a vast effort was being expended in the rapid deciphering of the Enigma code. Although a very small part of over 1,500 Voluntary Interceptors, East Lothian, in the form of Mr Amos and Mr Coventry, played a minor, but nonetheless very important, part in the ultra secret work at Bletchley Park. From this work, the British High Command was able to build up an accurate picture of enemy disposition and intentions and this intelligence work, which depended on the interception of German radio transmissions, was of vital importance to Allied success in the Second World War.
The interesting, but highly unorthodox, details of the recruitment of Mr Amos have also recently emerged. Early in 1940 three men called at his home in Templedean Crescent, Haddington. Mrs Amos answered the door to find a senior Edinburgh Police Officer who asked to speak to Mr Amos privately in his back garden. Needless to say, this upset Mrs Amos, who feared her husband had fallen foul of the law in some way. The three men explained to Mr Amos that they wanted him to cany out some very important war work relating to his training at Leith Nautical College as a Radio Operator. This was to be his introduction to the Radio Security Service! It was later discovered that of the other two men who visited Mr Amos that day, one worked for the Security Service (MI5) and the other was an officer in the Royal Signals, Captain Wallace MC., who was controller of a group of Voluntary Interceptors in the south of Scotland. Technical support for their work was provided from West Garleton House.