This article is reproduced by permission from the RSGB. It reflects research Paul did for the BBC to produce the documentary “Secret Listeners” which you can watch here. The sudden death of a great friend of mine, Hugh Lawley, G6ZG, prompts me to try to achieve a little more recog­nition for a now diminishing group of radio amateurs who made a unique and seemingly invaluable contribution to British and Allied Intelligence during the second world war. With the showing on BBC2 last year of the television pro­gramme “’The Secret Listeners” (for which I had researched for more than two years), the story was revealed of how almost 1,500 British amateurs and other morse operators had served during the second world war as “Voluntary Intercepted* (Vi’s), after over 35 years during which virtually no detailed in­formation had leaked out. But there are still many present-day amateurs who know little of the story.

Approach by RSS

It began in 1939 when Arthur Watts, G6UN, the then President of the RSGB, was approached by Lord Sandhurst, an officer in the Security Service (MI5X to find out if radio amateurs (who were officially closed down on I September) could help in set­ting up a radio listening watch on behalf of the Radio Security Service. RSS was much concerned that enemy agents might try to set up mf air navigation beacons in this country to guide hostile aircraft, or possibly try to contact Germany by means of hf radio. Arthur Watts responded enthusiastically; he felt this was a golden opportunity for amateurs to show they could make a useful contribution during wartime—and indeed the idea of an amateur “listening watch”  had been mooted during the first world war. Gradually, under oaths of secrecy, he talked to some of the leading dx and contest operators of the time; then, in spreading ripples, the bulk of amateurs with useful cw ex­perience were roped in—or at least those who had not already been “called up1″or joined the Services as members of the 1932 Royal Naval Wireless Auxiliary Reserve (RNWAR) or the 1938 RAF Civilian Wireless Reserve (CWR). By spring 1940 this new and shadowy organization of Vi’s ensured that there were “secret listeners” spread all over the country.

The practical problems facing civilian spare-time interception were far from negligible, particularly after the fall of France made invasion a real possibility. Amateur transmitting equip­ment had been impounded at the outbreak of war, and any sounds of morse attracted attention; a number of Vi’s were reported by suspicious neighbours as enemy spies, If there had been a successful invasion their position as undercover listeners for the Security Service would have been interesting. To provide “cover” they were later enrolled into the Royal Observer Corps, although some eyebrows were raised when it was noticed that they could not always tell a Blenheim from a Junkers 88. Initially, Vi’s were instructed simply to listen for anything unusual, gradually being provided with guidance as to what was not wanted. The mass of enemy and Allied Services traffic was the responsibility of the Services, enemy transmissions be­ing covered by “Y”, the joint Services intercept organization, in which a number of pre-war amateurs were already involved.

The great discovery

The Vi’s, if truth is to be told, found no mf beacons and few genuine enemy spies in Britain. For from the outset of the war German agents, as they arrived in this country, were quickly located (for reasons that will emerge later) and often “turned” into double agents, controlled by British Intelligence in what became known as the “Double Cross” system, sometimes with British amateurs at the key of the German “suitcase” sets (which often required skilled adjustment before they could be made to work). But the Vi’s stumbled on to something infinitely more important than a few lone German spies would ever have been, a spreading network of German secret communications links between stations in Berlin, Hamburg, Vienna and Wiesbaden and outlying German Intelligence posts in occupied and neutral countries and in ships. Some were radio links with agents in the field, but many more were the busy circuits to the “Asts” and “KOs”—the main Abwehr and RSHA offices in the towns and cities. A few were dx circuits to North and South America. These stations used the techniques of “clandestine” radio: for example, callsigns were not linked and were frequently changed; out-stations could reply on any one of several fre­quencies; stations seldom used a “net” frequency, etc. It was quickly realized that while Vi’s were hearing and logging these stations, little or nothing of this traffic was being reported or intercepted by the official “Y” organization. The Vi’s seemed to possess a “sixth sense” in sniffing them out from the vast mass of wartime w/t traffic. Possibly this was because many of the German operators were former amateurs themselves and tended to engage freely in “chat”; possibly because their transposition ciphers tended to have a different “feel” to the military substitution codes.

The Vi’s duly filled in their RSS log sheets and sent them by post to headquarters, which for a time was located in the cells of Wormwood Scrubs prison, but which soon became the cryp­tic POBox 25 that was in reality Arkley View, Barnet, in North London. Here RSS set up its discrimination and traffic analysis unit, manned in part by amateurs, to keep tabs on this in­teresting and growing German radio activity and to extract all possible signals intelligence from the logs before passing the coded messages to the Government School of Codes and Ciphers at Bletchley Park (Station X or “BP”), some 40 miles north-west of London. The logs were marked with comments such as “Watch please” or “OK covered thanks” or “More please” and then returned to the Vi’s to show what to look for and to spur them on to even greater efforts. In some areas the Vi’s were formed into local groups under a VI group leader who in turn was responsible to regional officers of RSS located in various parts of the country. The regional officers, each with a small staff, held occa­sional meetings with the group leaders, or directly with the Vi’s, to encourage them to spend many hours diligently searching for and copying stations which sent messages that meant nothing to them. By 1941 the logs were flooding into Box 25, reaching a peak of 10,000 pages in a single day. There was just one highly unfortunate breach of security. In circumstances that have never been fully explained, the Daily Mirror in February 1941 published a report headlined “Spies tap Nazi code” that described, at least in outline, the VI system. It could not have come at a worse time.

For at first only the relatively low-grade “agent” codes had been readily deciphered at Bletchley Park; the great bulk of the five-letter cipher traffic sent to and from Germany was as meaningless to the BP cryptanalysts as it was to the Vi’s, but then, towards the end of 1940, things developed in a way that underlined the remarkable success of the VI system, yet at the same time also sowed the seeds of its later decline.

The German traffic

From about December 1940, BP began regularly to break into the vitally important transposition hand codes used for the majority of the messages to and from the Ast and KO out-stations. Soon British Intelligence was reading, daily, dozens of top secret messages about the plans and activities of the Ger­man Intelligence services all over Europe. This, it can be argued, was as valuable to the Allies as the “Y” interception of Enigma machine-code messages of the German Air Force and (later) the German Navy—the key intelligence material distributed as ULTRA. For the Germans had one extra­ordinarily careless cryptographic practice; they frequently re-encoded messages received in a relatively low-grade code, word for word, into a higher-grade code for retransmission. Apart from the intrinsic value of the Intelligence traffic, there are some who firmly believe that it was often the Abwehr/RSHA messages that helped BP solve the Enigma keys so quickly that they frequently read the German military traffic before it reached its intended destination. There is also no doubt what­soever that the ability to read over the shoulder of the German spy chiefs played a vital role in the Allied deception plans (many of them based on double agents) that saved countless thousands of lives during the landings in North Africa, Italy and France. Effective though the VI system had proved itself during 1940 at finding and collating the German secret communi­cations, spare-time listening could not be expected to cope with regular interception of all this traffic, much of it sent during the Vi’s working day. The system had become too successful.

Furthermore, RSS was a creation of the Security Service, but those who were concerned with Intelligence activities on the Continent were members of the Secret Intelligence Service (MI6). With considerable reluctance, and following the in­tervention of Sir Winston Churchill, a joint arrangement was agreed between the different organizations. A special intercept station would be built and manned by operators drawn largely from the ranks of the Vi’s. As a result, from autumn 1941 many of the erstwhile radio amateurs were enlisted into Special Com­munications Unit No 3* and found themselves at Hanslope Park, a country estate conveniently near to BP and to Whaddon Hall, the secret service radio base. Even before the perma­nent station had been completed in May 1942, Hanslope Park became known as “The Farmyard”, and is still remembered half-affectionately by those who served there as the longest lasting, if most frustrating, Field Day of all time. The station provided a 24h watch on the many German networks that had been uncovered by the Vi’s; other smaller stations were set up in Scotland, Cornwall and Northern Ireland. A network of hf df stations was established to keep tabs on the locations of the many fresh out-stations that the Germans kept establishing.

At the time, the former Vi’s, knowing nothing of the high-level arguments as to who should have control over them, found it difficult to take kindly to the uniformed ambience of Hanslope and felt let down by RSS. This mood was heightened at the end of 1941 by the departure from Box 25 of Lord Sand­hurst, who had established an extremely strong rapport with “his” Vi’s. He moved to another branch of SCU at Whaddon Hall, where later he was able to bring in from Hanslope a number of ex-Vis. A few Vi’s became full-time interceptors in their own homes; the others were mostly put on to “general search”, seeking out new stations in allotted frequency bands. A still extremely useful but perhaps altogether less exciting “hunt” than in those heady days of 1940-1 when they first found and put together the networks (or “groups” as they were called) and became, admittedly by accident, an important and unique “source” of information about what was happening in occupied Europe, the unpleasant “surprises” that were being prepared for the Allies, and the fruitless attempts to infiltrate spies into the UK.

Some, though by no means all, Vi’s had an inkling of the part they were playing in the war effort; others were left in ig­norance on the “need to know” principle; virtually none was told of the deciphered contents of the messages. Some of those who joined SCU3 came to know a good deal more, and some were drawn into aspects of Intelligence that even today have not been fully revealed and are still subject to the Official Secrets Act. Military historians are just beginning to catch up with the role of Sigint between 1939 and 1945 but tend to concentrate on the code-breakers at BP rather than on those who had the often equally difficult task of plucking the “goodies” out of the air. Unfortunately inter-departmental and careerist rivalries persisted. At the end of the war in Europe, those who were still Vi’s received an undistinguished certificate signed by H. J. Greedy of the War Office thanking them for their efforts; a few, a very few, received the BEM, an award that some may feel hardly reflected the importance of the role they had played in making possible British Intelligence’s greatest coup of all time. Otherwise, at least until “The Secret Listeners” was screened, the whole VI-SCU3 set-up remained unacknowledged, even during recent years when book after book has told the story of Ultra, Enigma, Bletchley Park and Naval Intelligence.

The former Vi’s themselves tend to shrug this off, recognizing that secret intelligence often needs to be kept secret; that they have much more to be thankful for than those British, American and European amateurs who gave their lives or suffered unspeakable hardships in serving their countries as civilians, Service personnel or in the Resistance movements. But it saddens me, as someone of a later generation than the Vi’s, that many of the names and callsigns that have appeared increasingly of late in the obituary column of Radio Com­munication have only rarely carried any hint of their work as Vi’s. Much of the material I collected during the making of “The Secret Listeners” is now with Pat Hawker, G3VA (whose help in putting together these notes I gratefully acknowledge). It is hoped later to publish a comprehensive account—in so far as this is possible—of the role of British radio amateurs in the greatest, if saddest, amateur radio contest of all time.

Pat Hawker G3VA writes

SCU3 was one of about a dozen Special Communication Units, under Brigadier Richard Gambier-Parry (former G2DV) engaged during the war in a multitude of covert and semi-covert activities on behalf of the Secret Intelligence Service (MI6). The counterpart organization in Ger­many—Signal Regiment 506—similarly contained many whose early operating experience had been gained on the amateur bands: they pro­vided radio communications for the Abwehr (Military Intelligence) and the altogether less savoury Reichssicherheitshauptamt (RSHA) into which the Abwehr was later incorporated. RSHA included the notorious Sicherheitsdienst (SD) and the Gestapo, though there appears to be no reason to suppose that German amateurs, drafted into the regiment to work for Intelligence, took any active part in the type of activities with which, unhappily, we associate the parent organizations. The largest radio network (Group 2) was based on Berlin, with particularly active links to many intelligence posts (including shipping observers) in the Iberian peninsula, Norway, the Balkans and Asia Minor.