Special Duties Branch, Auxiliary Units

The Special Duties Branch of the Auxiliary Units was arguably the most significant part of the Auxiliary Units but the latter's role has been greatly distorted by the romantic mystique of its hidden wireless stations and operational bases, which have contributed greatly to the post-war myth of this being a 'resistance' organisation.

The SDB was the intelligence wing of the Auxiliary Units, organised on a quite different basis to the Operational Branch. It was directly inherited from the Home Defence Scheme of SIS, with former (?) SIS officers continuing to manage it into 1941. The Special Duties Branch effectively remained a separate organisation with the wider concept of the Auxiliary Units and the War Office struggled with how best to manage the inherited resource. Hugh Dalton in July 1940, when battling for the creation of SOE out of War Office control, declared that clandestine warfare was ‘no more suitable for soldiers than fouling in football or throwing when bowling at cricket’. He may have had the Auxiliary Units in mind, with many early senior officers coming as they did from a heritage in MI(R) [see Pioneers of Irregular Warfare] - which had a poor record in managing practical clandestine projects. As a consequence of its direct SIS ancestry, the SDB was the only part of the Auxiliary Units that had a truly civilian element. Most of the c.1,000 SDB agents in 1940 are likely to have been recruited by Section D. The latter could by deliberately vague as to the precise authority of its officers and in some areas there was a complicated crossover.

In 1939/40 there was still a good deal of suspicion within both the War Office and SIS on the reliability of wireless both for battlefield communication and collecting intelligence. The original function of the SDB was confused by its inheritance from the Home Defence Scheme of SIS Section D, which at the time was trying to move from serving as an anti-invasion guerrilla force to something more akin to a long term resistance (to the dismay of SIS HQ who saw this as a potential threat to the security of the actual resistance in Section VII). The driver of War Office interest in the HDS had primarily been to take over itsguerrilla resources, but it discovered that the Intelligence (Special Duties) branch of the HDS came as part of the package! As the SDB, this intelligence network now had to be converted into a form that the War Office (who were never in the business of creating resistance organisations and for whom this concept was abhorant when applied to Britain) could use. Thanks to Section D, the initial methodology was drawn from traditional SIS pre-wireless practice - but was a methodology best applied to occupied or neutral countries having settled conditions. It consisted of a ponderous mechanism of agents, 'runners' and 'cut-outs' passing on written messages. Crucially, their main contact was with just a small number of Intelligence Officers scattered around the coastline of the east and south coasts. The latter were, in the main, not fit young 'James Bond' types but older men selected because they could be spared from front line service and they had no guerrilla warfare training themselves. The War Establishment of 11 July 1940 allowed for just 11 Intelligence Officers to cover the whole country, plus 2 officers at HQ. Such a system was poorly designed to fulfil the current War Office expectation that the SDB would provide immediate battlefield intelligence in what was expected to be a rapid 'blitzkrieg' with no settled front line to cross. This was despite the optimistic intention of the Auxiliary Units (at a time when its CO admitted to 'cranking up' the organisation to secure govrnment support) to ‘provide a system of intelligence, whereby the regular forces in the field can be kept informed of what is happening behind the enemy’s lines.’ In practice, any intelligence the SDB gathered using this method was likely to be out of date before it ever reached its destination. The main notification of enemy presence was likely to come from the telephone-equipped Coastguard Service and Royal Observer Corps, quickly providing intelligence for the mobile 'Phantom' patrols of the GHQ Reconnaissance Unit to move into a target area. It was 'Phantom', considered the only unit in the BEF that had reliable wirelesss communications, that was given the main credit for collecting battlefield intelligence in 1940. There was no intention that the SDB would serve any 'resistance' function, especially as the assumption was that the Operational Branch, with whom they had no official contact anyway, would be wiped out in a matter of days. Instead, 'resistance' was left as a matter for SIS Section VII. A key principle of SIS strategy in encouraging early resistance organisations abroad was that this should be layered. One body would provide a short term response to invasion but in the expectation that it would not survive. This should have no contact with a more permanent resistance organisation that would take no part in the actual invasion, in order to protect its existence. This was a principle also carried forward into the Cold War. It is easy to see how this principle applied to the SDB in its relationship to Section VII.

From 1941 the SDB was finally able to develop a wireless network based on the novel TRD VHF set and using as a model the pyramid structure of the Observer Corps posts (which used a dedicated field telephone system). The principal attraction of the TRD was that, as in the Observer Corps, its system of voice transmission made it suitable for mass civilian use without the need for extensive training. Although an undoubted improvement on the initial reliance on 'runners', the Special Duties wireless network, despite the ingenuity of the hidden OUT Stations, was still likely to be broken in the first days of invasion - as soon as the army HQs and the associated IN Stations (sited in surface nissen huts until 1942) were either obliterated by dive bombing or obliged to move location in what experience suggested would be a fast-moving campaign. Nonetheless, in those first few hours or days after invasion they could have provided a valuable source of intelligence on the initial enemy landings after the Observer Corps and Coastguard posts had been wiped out.

The self-evident limitation of the TRD in any longer-term 'resistance' scenario is demonstrated by the fact that the Control IN stations, located just c.15 miles from the coast, relied on the continued presence of army support via Royal Signals or ATS operators from Auxiliary Units (Signals). The wireless network as a whole was entirely dependent on a continuing Royal Signals presence to ensure its fixed directional aerials maintained a link to the IN stations, which were based at army HQs. Until 1942 the IN Stations were sited in surface huts, vulnerable to dive bombing. Ironically, the underground IN Stations were only provided from 1942, as the risk of invasion was decreasing.

Today the attraction of the iconic hidden wireless stations obscure the fragility of this system. Nonetheless the wireless network could have played some part in the wider notification system (alongside Coastal Service and Observer Corps) that was designed to provide an important, albeit brief, notification that the enemy blitzkrieg had penetrated a locality, so that the 'Phantom' units could deploy to that particular area. Ironically, the original system of 'cut-outs' and 'runners' may well have played only a minor role in this plan, speed of transmission being of the essence - but their time would come!

A key part of the post-war legend of the TRD was that it was undetectable. This was known at the time not to be true but was a useful tale to maintain the morale of the wireless operators, in the same way that Intelligence Officers of the Operation Branch sometimes misled the patrols. The transmitted messages were indeed indecipherable unless received on another TRD, but the signal itself was detectable beyond its operating range of c. 30 - 60 miles. At least one of the hidden wireless stations was detected by military units looking for enemy radio sets. As proof of this, in 1944 the network was included in the countrywide deception programme prior to D Day, when every army wireless network participated in pre-determined spells of radio silence or intense radio activity, so that the enemy would not be able to use levels of radio traffic as an indicator of coming invasion. During this periods of activity the SDB wireless operators transmitted knitting patterns or pure gibberish, simply to fill the airwaves.

As an indicator of the low priority of the system, underground IN Stations were only incorporated into the system from 1942, even as the risk of being ever used in an invasion contet was decreasing. Also from this period, an increasing number of the wirelsss sets were now the notoriously noisy (and out of date) WS17 sets - easy to locate and a clear indicator that the network was not seriously intended to contribute to secret battlefield intelligence. By 1944 around 40% of the SDB wireless sets were the WS17. It weas only from 1943 that the SDB were included in the emergency broadcasting sysatem of BEETLE, long after units of the Home Guard. However, what the network (particularly the IN Stations) could provide from 1942 was a means of quickly reporting an enemy raid on the associated army HQ. The possibility of 'spoiling raids' was something taken seriously in the run-up to D-Day, although the Auxiliary Units Training Officer, Nigel Oxenden, expressed some contemporary cynicism in describing the rumours of raids as ‘a gift to IOs’ and ‘a wonderful tonic for fading enthusiasm in the ranks’. He went on ‘Sceptics wondered whether it was ever intended as anything more. The effects, with careful nursing lasted for the next two years.’ By then, the wireless network was surviving larely through bureocratic inertia and the 'anti-invasion' training and exercises increasingly (as in the Operational Branch) take on a self-delusional aspect as Auxiliary Units HQ strove to maintain the interest and morale of the operatives. The value of the SDB was now in a very different, even more secret, function.

Replica of the TRD wireless set, configured as an IN Station set with separate receiver and transmitter tuning dials (a complexity not required on the OUT Station sets), together with standard telephonist chest microphone.

It was short range VHF set (with a normal range of 30 - 60 miles) that used voice transmission (and therefore required minimal training - allowing a civilian network to be quickly established). It was not the super-secret set of legend and although its signal could only be deciphered by another TRD set, the signal was not in itself undetectable. Instead, the TRD relied for security on its use of rarely-used VHF frequencies and a very directional aerial. The latter meant the TRD set was inherently unsuited to clandestine warfare as both the IN and OUT station had to be in fixed locations.

(replica by Malcolm Atkin)

The WS17 set was designed for short-range communication for barrage balloon control, and between artillery and searchlight units in fixed locations. It used the same VHF frequencies as the later TRD set and suffered from the same limitations of reliance on a directional aerial.

The set was extremely noisy - enough to cause problems with low flying aircraft! Nonetheless, by 1944 (although out-of-date even at the time of issue) the WS17 comprised 40% of the wireless sets used by the Special Duties Branch of the Auxiliary Units.
photo © Susanne Atkin

The Special Duties Branch proved to be most important as an internal security body. Although the wireless network soon became redundant as an anti-invasion network, it was now that the the growing number of local civilian agents (3,2500 in 1944 according to their CO) came into their own, assisting MI5 and Military Intelligence in eavesdropping on the loyalty of the British populace and monitoring any careless talk among the troops massing for D-Day. This was the main contribution of the Auxiliary Units singled out for praise at its stand-down in 1944. Ironically, the wireless system and its iconic hidden wirelss stations may have played little part in this process, which might partly explain why so few of the sources, who were primarily connected with running the network, mentioned the security role. Instead, this was now a new role for the agents and cut-outs whose whole rationale was that they never knew where their messages were ending up. The paper messages left in dead letter drops allowed photographs of suspects to be circulated and then directly collected by the Field Security Section of Military Intelligence. An exercise using the wireless network whereby such information was collected through the cut-outs and then sent along the system of SUB-OUT, OUT and IN Stations, before being forwarded for collation at the Coleshill HQ before being sent to Military Intelligence was ponderous by comparison.

For veterans, the security role was less dramatic than any function in reporting the movement of enemy invaders. It was also very sensitive in that after the war the civilian agents may have been reluctant to admit that they had been spying on their neighbours. It was far more romantic after the war to focus on the notion that, for example, a teenager might be given the unrealistic task of roaming the countryside on horseback to report back to her father's wireless station on enemy movements. This story comes from 1942 in East Anglia, when the area was beginning to be flooded, not with invading Germans, but by US servicemen! Had it ever been seriously considered that the story of a young girl going out to exercise her horse during the first days of invasion (in the period before the wirelss network collapsed) would be a believable cover story?

In a clear demonstration of the incomplete nature of the sources, no mention of any security reports has ever been made by SDB operatives and none have survived but the role was referred to by Major Peter Forbes, the officer in charge of the SDB from August 1943, who maintained ‘it was probably the most important SD [Special Duties] work’. This was confirmed in July 1944 when the C-in-C, Home Forces, General Franklyn, wrote to the CO of the Auxiliary Units ‘In recent days while our own invasion forces were concentrating, an additional heavy burden was placed on those of you responsible for the maintenance of good security, to ensure that the enemy was denied foreknowledge of our plans and preparations. The Security Reports regularly provided by Special Duties have proved of invaluable assistance to our security staffs’. After the war, the significance of the security role of the SDB is demonstrated by the fact that SIS insisted that its civilian volunteers should receive no public acknowledgement, whereas the Operations Branch qualified for the Defence Medal (subject to appropriate length of service). As the Cold War approached, who knew when these men and women might be quietly be called upon again to spy on their neighbours! The earliest published accounts of SDB veterans date from 1945 when there was a rash of newspaper reports describing the Auxiliary Units as a whole. During the Cold War there was a renewed concern for security and most veterans took their secrets to the grave.

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The first detailed history of the Military Intelligence (Research) department (MI(R)) of the War Office. This was not a body that was primarily concerned with conducting operations in the field, but it established the doctrinal framework that led to the creation of the commandos and SAS.

Published by Pen & Sword, 2021.