The Voluntary Interceptors (V.I.).....

The Radio Security Service (The RSS)

"The Secret Listeners"

Frank Forbes G2BFC

This page was put together by my brother Tim a keen radio ham and proud owner of my fathers callsign, which has been in the family for some 65 years now !

I am most grateful to Tim for the time and effort he has put into researching this piece and his enthusiasm and whole hearted commitment to amateur radio. Unfortunately I never had the inclination to follow in his and my fathers footsteps, opting for a 25 year career in the Royal Navy & Royal Marines.

This then is Tim's piece on the V.I.s

"I'm the proud owner of my fathers old amateur radio call sign of G2BFC. This was first issued on the 31st May 1937 using the call sign of 2BFC (the G in front came after the war). Unfortunately, my father died when I was only about 6 years old, but I still remember siting down with him listening to Morse code being sent over the shortwave bands on his home made valve equipment. In around 1984 I started to hunt for my fathers call sign. By getting in touch with the Radio Society of Great Britain (RSGB), I not only found my fathers old call
sign, but my mother started to tell me about my fathers activities during the war years which had never been told before.

Hunched over his HRO radio set at all hours of the day and night in a shed at the bottom of the garden. He would note down the Morse code on a given frequency and log everything. To his dismay, the house was surrounded by the Police and Home Guards when he was in his shed one evening doing his normal duties. A neighbour had informed the Police he may be a German spy because they could hear Morse code coming from his shed late one night. Some how, he was able to satisfy the Police and Home Guards that everything was alright, without actually having to tell them what he was doing.

The story of the Voluntary Intercepters (V.I's) unfolded as I started to gain more information about them. The Radio Security Service (RSS) recruited all radio amateurs who, for one reason or another, were not called up. They were recruited to monitor Morse code (CW) radio transmissions during the war Years.

A very few, like my father, actually transmitted as well. This is their history".

The Voluntary Intercepters of WWII

At the outbreak of hostilities, MI5 introduced one of its contingency plans to deal with the problems of illicit signals. To cope with what was perceived to be a major headache, MI5 created an entire new body, the Radio Security Service, under the leadership of Major J. P. G. Worlledge, the veteran interceptor who, until 1927 had commanded the No. 2 Wireless Company in Palestine.

He was given a brief 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" Lacking both permanent stations and staff, the newly created RSS was obliged to build an entire organisation on the outbreak of war.Worlledge selected Majors Sclater and Cole-Adams as his aides and placed Walter Gill, of War , Wireless and Wangles fame, as his chief traffic analyst. It only remained to find some suitable illicit signals, and Worlledge opted to rely on a network of radio amateurs working in their spare time. Many had volunteered the previous Year to join the RAF's Civilian Wireless Reserve, a shadowy group of the RSGB operators which paralleled the Royal Navy's Wireless Volunteer Reserve.

As a security precaution, the RSS was granted the military intelligence cover designation MI8c. The task of developing a comprehensive organisation was given to Lord Sandhurst. An enthusiastic amateur licence holder, Jimmy Sandhurst with the Royal Engineers Signal Service in France during the Great War, where he had led a group of owner-rider despatch riders. He had joined up in August 1914 as a lance-corporal and had been commissioned soon afterwards. Educated at Winchester and Trinity, Cambridge, he had succeeded to his father's barony in 1933. In September 1939, he had been commissioned into the Royal Corp of Signals with the rank of Major, given an office in the Security Service's temporary headquarters in Wormwood Scrubs Prison and instructed to liaise with R. L. Hughes, a wartime recruit into MI5. Sandhurst's first act was to approach the President of the RSGB for assistance.

The then RSGB President was Arthur Watts, a veteran of the Great War who had lost a leg at Gallipoli and had subsequently become a traffic analyst in Room 40, Watts recommended the recruitment of the entire RSGB Council and, after routine security clearance, all were indoctrinated into the RSS.

Because nothing has ever been officially disclosed concerning the work of the RSS, this is an appropriate moment to describe its activities in some detail. It will then become evident that it was largely thanks to the RSS that the cryptographers at Bletchley Park were able to continue their work.

In many ways the RSS was a classic example of time honoured British improvisation, with voluntary workers making considerable personal sacrifices to rescue the ill-prepared Whitehall establishments. During the first few months of war, domestic interception in Britain was limited to the two War Office stations at Fort Bridgewoods and Flowerdown, with some additional work being carried out by the new GPO stations at Sandridge, St Albans, Cupar and Brora. The latter three concentrated on a futile search for navigational aids, known as meacons, which the Luftwaffe was believed to have constructed in secret locations across the country. In fact, none ever existed, but while the GPO was otherwise occupied, the business on monitoring illicit radio transmissions fell to the RSS. In addition, direction-finding stations were built at Thurso and Forfar in Scotland, Bridgewater in Somerset, Gilnahirk in Northern Ireland, St Erth (which was largely underground, just outside the village of Leedstown) in Cornwall, Wymondham in Norfolk, and Hanslope Park; seven in all.

Mobilising a volunteer force was by no means easy, especially in conditions of great secrecy and without any special equipment. Sandhurst once warned: "The VI is under obligation. He has written his good name to that effect. If he does talk too much he may find himself in a jug. In almost any other country in Europe he would be shot."

The operators had to be skilled, discreet and dedicated, so the recruitment process was necessarily slow. By Christmas 1939, the Home South region boasted only seven VI's on its roll. Their task was particularly arduous, with several hundred enemy's signals to monitor. Furthermore, intercepting the enemy's signals was no easy matter. For example, the BBC was accustomed to Broadcast its entertainment programmes at a strength of 100 millivolts per metre. The loudest German signal was 10,000 times weaker, and the weakest were a million times below the BBC. Nevertheless, in spite of these difficulties, Sandhurst proved to be a popular, inspired leader and introduced an element of humour into his personal messages of encouragement to his volunteers.

He also produced a fortnightly newsletter, entitled The Hunt, in which he referred to himself as "Dogsbody" or "T. W. Earp," the enemy as "Foxes" and "Skunks" with friendly Service stations labelled as "Rabbits." Sandhurst even composed a poem to explain the procedure to new VI's:

The first task of the VI was to distinguish between the various different types of five-letter ciphers being transmitted in Europe. They fell broadly into three separate categories: the commercial traffic, which generally used the international Q-code and could easily be spotted by its automatic transmissions at a uniform pace. If there were no texts to be sent, the circuit would be kept open by a continuous signalling of "ABC". Commercial messages invariably concluded with a time or date. The only two exceptions were the Russians and Spanish inland telegraph services, which were still largely manual,but their procedures were equally easy to distinguish. The second category was the British armed services, which used the same call-sign format of three letters, with mixed figure and letter. There were other easy clues in the Rabbit traffic, such as the inclusion of a five-figure group of "QQQQQ" which British operators with pre-war amateur experience habitually transmitted, given the opportunity. Each country had its own characteristic procedures, and the patient interceptor would gradually learn them all. The Italians, for example, used a five-figure cipher in which every tenth group was numbered; the Russians invariably inserted the letter "R" between their groups, and the Spaniards used groups beginning with the letter "P." Thus, P2371 was sure to come from Spain and, therefore, to be of no interest, and the German army often finished its messages with a six-figure group, which also told the interceptor to scan another frequency.

The third category, which was supposed to be left to the army and Admiralty interceptors, was the German army and Naval traffic. The Wehrmacht signals always opened with their distinctive preambles, and the Naval transmissions were usually sent in four-letter ciphers by very steady operators using exceptionally good Morse. They were also trained to repeat the first two groups of the preamble as the last two on the end of the message.

Once the VI had eliminated this traffic, he was left with the more interesting, and secret, foxes. These were enemy point-to-point messages which were quite unlike anything else and contained very high-grade intelligence information, either between an Abwehr agent and his base, or two Abwehr stations. Sometimes the call and reply would occur on different frequencies and employed a variety of such manoeuvres to avoid interception. By doing so, they actually attracted attention to themselves and thus aided the RSS interceptors, who became very adept at spotting unusual preambles or operating procedures. It was these out-of-the-ordinary intercepted signals which were to give the Bletchley Park cryptographers some of the breakthroughs for which they had been waiting. Some of the crafty enemy operators quickly established themselves as "dardiddley-dar merchants" by first signing off and then starting to transmit a few moments later. The really clever opposition stood out from the usual routine of poor security and the exchange of private messages of initials, and proved very popular with interceptors. One game, known as "finding the lady," involved checking the previous schedules to work out which outstation a particular fox would operate to next.

One of the first circulars issued to the VI's included a description of a few notorious foxes:

ANNA is a very delicate lily, the flower of them all, our beautiful heroine. Often may you see her flitting gracefully through the bluebells, or in and out of the kilocycles. She is demure; she speaks not often, but when she does it is clear and sweet, and her utterances pearls of priceless worth. Anna dresses well, and thirty times a month you will find her in fresh apparel. She is tall and slender, and her long arms may reach across the ocean. You will always know her by her simple preamble: CT ANNA PURE AND SHY BT.

BRUNO is a young gentleman who lives mostly in the North of France. Like Anna, he does not say much, but he is easy recognised by his clear Group 6 voice. Sometimes his hand is a little uncertain, but he always tries to be smart, and changes his suit daily.

CAESAR is the village idiot. He spends most of his time talking to himself, but even then he has to repeat everything many times before he gets it right, with his rough ICW voice and his Group 7 accent with the dreadful sss-stammer.

DORA is the elusive witch. We don't see much of her, she is always hiding on skunk or commercial frequencies. Her preamble varies. Sometimes she tries to pass as Anna, but spends too much time with the skunks to make the illusion a success.

EMIL and his wife Ada are the old folks of the Group 3 family. They are dull and stupid, and MOST prolific. Their family is so large that they have been entirely unable to rear and discipline them. Ada's Group 2 chromosomes have come out strong in many of her offspring, but the old man's Group 3 have contributed a very unruly element. Their children include Gun de Sie, the only ones not always wanted by the police, the elusive OLM and ADF, the ugly great leering Fritz, and those dreadful BUM boys.

FRITZ a great fat ugly good for nothing lout struts all around six bands sowing his filthy oats all the time. Wherever you look amongst the kilocycles (bluebells wilt) you will find his illegitimates grinning at you. They talk all day, their fat mouths giving away everybody's secrets, trying to dodge the police, for they are all very much wanted.

The BUM boys. These highly disreputable nancies, sorry, Nazis, have never even leaned to use a preamble when they speak. They use wicked words, they can't spell, and, not satisfied with that, they can't always send Morse. They have got a way of vanishing round the corner just when you think they are going to give you something, and then come up behind you, round another kilocycle to shout their ruderies..... There is a price on their heads.

Fox preambles were a little different from the Enigma messages because, as a manual cipher, there was no "discriminant" rotor setting to be chosen. Instead, they consisted of date, time, serial number, the "indicator" (to identify which code was to be used), followed by two figures: the total number of letters in the message and the total of groups. The more a VI concentrated on a particular fox, the more skilled he became. The RSS management reckoned that the minimum product for a reasonable VI was eight logs a month; most started with an average of ten, but forty-eight was the minimum to ensure exemption from other duties, such as fire watching.

Within three months of starting work, RSS had recruited fifty VI's and identified approximately 600 foxes, but they were all firmly on the other side of the English channel. In December 1939, the number of logs submitted by the Home South section produced a total of 1,932 logs. By March the following year, the figure had jumped to 3,052.

These logs of Morse messages collected by the VI's on their own private sets (later to be issued with HRO's) were sent into RSS headquarters at Wormwood Scrubs via their regional officers. Sandhurst had appointed twenty regional officers to supervise the work of the VI's and to allocate particular frequencies on a routine of watches. The country was divided into RSS regions, which were identified by letters denoting geographical areas. Those closest to London became Home North and Home South, and individual VI's were allocated special code numbers, based on their geographical region.

Logs signed by SW/127 immediately identified the operator as J. W. Clayton of Fowey in Cornwall, and NW/185 as Gerry Openshaw of Bolton in Lancashire. The VI's would return from their regular work in the evening and listen for three of four hours to a predeterminated wavelength. As the organisation grew, the country was further divided into sub groups, each headed by a group leader who was identified by a group number. In correspondence with headquarters, group leaders would head their logs "V. HS/120, Sub Group HNS4." Initially, the VI's concentrated on evening and night work, with hardly anyone available to work their sets during the day. With further recruitment, Sandhurst was able to fill the gaps with enthusiastic volunteers.

Before a code could be subjected to cryptanalytical attack, it was first necessary to intercept a series of examples of radio messages. The more texts available for study, the better the chances of cracking a code. However, the intercepts had to be copied with absolute accuracy. There was no point in attempting to solve a code with corrupted texts. The responsiblilty for getting the intercept 100% accurate rested with the interceptor, and if more than one could take down a message the opportunity for error was reduced. If the analysts could compare the handiwork of several different VI's, they would quickly spot the odd mistake.

Once received at headquarters, the VI's log was examined by discriminators who decided if the raw material was a hand cipher or machine code. Comparison with direction-finding reports gave additional information . These would identify the bearings of the sending station and be marked with the exact time of the message, its length and its frequency. Thus, by the time the intercept reached the cryptanalysts, they already knew a considerable amount about the texts background. They knew, for example, the location of the sending station and, if the receiving end acknowledged it, the recipient. If the location was a familiar one, it might identify whether the traffic was Abwehr, Wehrmacht or Luftwaffe. The length of the message and style of the sender might also reveal important details. If the intercept's distinctive preamble showed that an Enigma machine had been employed, the analysts endeavoured to work out which key had been used. If the key was recognised, it was examined for any mistakes that might give a clue to the content. When the discriminators had completed their task, the intercept would be passed to the specialist units staffed by officers who concentrated on particular kinds of enemy traffic. A message intercepted from Abwehr in Hamburg, for example, would go to the RSS sub-station which dealt with that material alone, and was equipped with a card index listing all the past intercepts and cross-referring those with similar characterists. The process of traffic analysis thus gave RSS a wealth of information, even if the exact content of a message might be elusive.

The rapid expansion of the VI network created so much raw material to be processed at Wormwood Scrubs that, early in 1940, arrangements were made to move out of London to the small village of Arkley, near Barnet in Middlesex. Arkley View, a large house on the outskirts of the village, was requisitioned and a staff of traffic analysts installed, led by Walter Gill. Among them were Denys Page (later Regius Professor of Greek at Cambridge) and Hugh Trevor Roper (later Lord Dacre, and Regius Professor of History at Oxford). Eventually, their numbers were to be swelled by three further Oxford academics: Charles Stuart, Gilbert Ryle and (Sir) Stuart Hampshire (now Warden of Wadham College).

Kenneth Morton-Evans received the VI logs mailed to "Box 25, Barnet" and divided them into a series of numbered groups, which sorted the logs into known and unknown stations, roughly identifying the origin of the intercepted signals. The groups ranged from GROUP 1 to GROUP 15 and were further sub-divided into actual wireless stations. Thus BERTIE on GROUP 1 was Berlin, HARRY was Hamburg and WILLIE was Wiesbaden. If too many VI's duplicated each other, their logs would be returned with remarks such as: "German Army, covered, thank you." Or a VI might be told: "Suspect more please."

On a good day "Box 25, Barnet" was receiving around 300 logs a day, with some of the logs covering up to fifty separate sheets. Analysis of this huge volume revealed that RSS was concentrating solely on the interception of enemy signals from the continent and not on the stalking of illicit signals from home, the job that the War Office had at first envisaged for them. This, of course, is not to suggest that the War Office was at all dissatisfied with RSS's performance. On the contary, it was quickly accepted that the RSS amateurs were far more skilled SIGINT interceptors than the so-called professionals of the GPO. The licensed amateurs were extremely practised at exchanging very weak signals from other hams around the world, often operating sub-standard equipment. In contrast, the GPO staff had only experienced very high-quality standards in signalling and were, therefore, ill-prepared for catching the faintest transmissions. Worlledge once commented on RSS's impressive ability to spot and monitor even the weakest of enemy signals: "We have continually wiped the eye of the Post Office over it, and I am very anxious that we should wipe it cleaner."

By March 1940, it was realised (not without some disbelief) that the RSS had actually completed its original mission. Incredible as it may seemed at the time, there were simply no illicit signals for the VI's to monitor.

According to the analysts at Arkley, all the intercepts were German in origin and consisted of station to station nets on the continent. However, instead of disbanding the VI network, RSS prepared a handbook of German Morse techniques and issued it to the VI's later the same month. This book was to prove of enormous benefit when, some eight weeks later, the Germans launched their offensive into Belgium, Holland and France. To the amazement of everyone at Arkley, the Abstelle at Wiesbaden was monitored sending special messages to its agents in those countries, alerting them to the imminent attack.

The Abwehr's increase in signal activity during the summer of 1940 was final confirmation that, contrary to all expectations, the Germans intended to rely more heavily on wireless communications. Evidently, they believed their hand and machine ciphers to be unbreakable, but there was a mass of other valuable intelligence to be gleaned from the ether. Gossipy German operators were comparatively undisciplined by British standards and tended to engage in radio chatter while establishing contact with another operator. The purpose of the exchanges was apparently to identify the particular operator at the other end of the net and proved very useful to RSS. By the end of the war, a special index of "personality cards" had been opened on several hundred German operators, and analysis of their geographical locations often helped to confirm the movement of certain military units. Sometimes the operators would discuss details of new codes, or agree the updated settings of their cipher machines or even debate the merits of a manual code. Another important advantage gained from these indiscretions was the opportunity to keep pace with the frequent changes in the call-signs of enemy stations. When an operator kept to a routine signal plan and transmitted at the same time each day, it was fairly straightforward for the monitoring VI to recognise his opponent's fist. Furthermore, if two Germans indulged in some chat, it enabled the VI to find the enemy's operating frequencies, because they did not, as a rule, net on the same frequency.

Arkley View had some 23,00 complete logs were being received a month by August 1941, comprising up to 10,000 sheets a day. Most were Abwehr hand ciphers, although there was also some duplication of the machine cipher traffic monitored at five big Service stations at: Cheadle, Waddington, Montrose, Beaumanor Hall and Chicksands Priory. The VI's had proved themselves to be totally committed to their tasks, but the growth in their numbers had created difficulties for the Services, which were unable to find enough qualified people to man their own intercept equipment at their bases. The first signs of a crisis had been spotted late in 1940, when the Prime Minister had asked Lord Hankey, then Chancellor of the Duchy of Lancaster, to investigate. At his recommendation, a number of RSS operators had been transferred into the services, a solution that had been bitterly resented by Worlledge.

The official RSS invasion instruction gives an idea of the bizarre conditions under which the VI's worked:

a. General watch over the 24 hours, covering from 0600 to 1700 5.5 to 9Mc, and 1700 to 0800 hours 3 to 6.5Mc.

b. Special group watching.

c. Find out from your employer if he will release you in the event of an invasion, so that as long as you are in unoccupied territory you can put in full-time watch.

HQ will arrange to collect logs from convenient centres, and we can possibly arrange to centralise receiving points.

The VI's recruited by Sandhurst's Regional Officers were dedicated to their craft and spent many hours a week hunched over their receivers, unable to tell even their families exactly what their duties were. As a cover, a "Special Branch" of the Royal Corps was invented, and the secrecy surrounding the RSS was only breached once - by the Daily Mirror on 14 February 1941 in a feature which inexplicably slipped past the censors and was headlined "SPIES TAP NAZI CODE." "Britains radio spies are at work every night," reported the Mirror Special Correspondent: "..........they sit, headphones on ears, taking down the Morse code messages which fill the air. To the layman these would be just a meaningless jumble of letters. But in the hands of code experts they might produce a message of vital importance to our Intelligence Service".

Although the article had begun, "Their job isn't one to be talked about.........," it contained a quote from an unidentified RSS operator: "Naturally we have no idea of the codes used by German agents. But is is a great thrill to feel you might be getting down a message which, decoded, might prove of supreme importance." This remarkable lapse caused tremendous agitation at Bletchley, but either the enemy ignored if or they missed it. Either way, there was no deterioration perceptible in the quality or the volume of traffic intercepted.

In a relatively short period, Jimmy Sandhurst had turned as amateur listening group into the most professional of organisations. The work of the VI's had been divided into "rota" ( a system that subsequently became known as General Search) and "freelance," which either allocated certain frequencies to named watches or gave the VI's a chance to initiate their own search schedules. Sandhurst later recalled:

"When we started out on this job at the end of 1939 all we had to do was cover the bands and wait for the local pirates to appear, and log anything suspicious. Well, the locals have never turned up but "suspicious" has produced a vast network of stations of great interest. As we got to know them we found that they were highly organised but not ordinary service stations, and as slippery as eels, trying to dodge all the time. It need a vast army of experts to keep track of them, and their output is valuable. We are the experts. The job has grown so that we can hardly do this and the rota watches as well. The chaps who do lots of rota don't have much chance; they have to keep on the move and find 'em. Having found 'em it is best to follow up daily and get to know them. Or maybe, take a slice of the ether, live on it, get to know its inhabitants. A lot of the wanted stations mess for a week and then shoot a message over quickly. The man who knows him gets it, the other more often doesn't."

RSS's extraordinary success at harnessing the radio amateurs was to cause political problems for the organisation. By eliminating the possibility of illegal transmissions, RSS had, in one sense, worked itself out of a job. RSS had been created under MI5's wing, in the belief that its role was a defensive one. But thanks to MI5's comprehensive action in rounding up all those on its Suspects Index, there was little hope of any Abwehr agent remaining at liberty.

A message obviously sent to all the VIs at the time. This is well after D-Day but probably designed to stop the listeners thinking their work was coming to an end and they could relax a little!

Thanks to my brother Tim - G2BFC - for the text.

My thanks to Niel Wiegand - W0VLZ - for the images of the HRO receivers. Neil's web site Radio Bay has much more information on the National Radio company and their products.

Copyright © 1995-2008 Andy Forbes [except where stated] All rights reserved. www.64-baker-street.org