SOE

by Fredric Boyce

  Upon call-up in 1940, Meldrum joined the Royal Engineers at Shorncliffe in Kent and soon took command of 141 OCTU. He was engaged in bomb disposal work in the Portsmouth area, which included the Isle of Wight. Almost a year later he was promoted to Captain and found himself posted to ISRB in June 1942 as engineering assistant at the engineering experimental establishment. Here he worked on the design, progress and development of midget submarines. Together with Dolphin and Porteous he was credited with the design of the trim valve for these craft.

  During the winter of 1944–45 when the Chief Engineer, Col Dolphin, was away he took over and was directly responsible to Newitt for a section of six officers and 194 tradesmen. In March 1945 responsibility for the establishment changed from SOE to the Admiralty and Meldrum became answerable to Commander G.E. Williamson. After the war he joined the No. 2 Laboratory of Courtaulds in Coventry as a research engineer on textile machinery.

  Working alongside Meldrum was Hugh Quentin Alleyne Reeves who had been born in Seaford, Sussex in late 1909 and attended Harrow School and Cambridge University, from where he graduated with a second class BA in Engineering in 1931. He joined J.H. Robinson and Co. of Liverpool as an assistant manager and in 1936 moved to Hazlehurst Consulting Engineers as a partner. He soon became joint managing director of the company and was concerned with boiler and electrical generating plant and water services. He was commissioned into the Royal Army Service Corps. Maj Reeves was probably the most prolific of engineering designers at Station IX, being concerned with a variety of projects from the Welrod and Sleeve Gun to the buoyant limpet and sucker device. He finished the war with the rank of lieutenant colonel. Postwar, Reeves became involved with the noise suppression of jet engines and tragically was killed while working on one.

  Durward (‘Dagwood’) W.J. Cruickshank, born 1924, arrived at Station IX in late July 1944 straight from an engineering course at Loughborough. C.P. Snow (who with Julian Huxley and Dr Bronowski starred in the BBC Brains Trust programme) travelled round Britain’s universities seeking talent for the Allied war effort. One day he interviewed Cruickshank at Loughborough and sent him off to Station IX for further vetting. He worked on the Welfreighter with John Oxford under John Meldrum and celebrated his twenty-first birthday the following spring. He was involved in a great deal of design and testing on the vessel both at The Frythe and at Fishguard before leaving early in 1946 to join Cox’s X-ray group at Leeds. He moved to a Chair in Chemistry at the University of Manchester Institute of Science and Technology and was elected to the Royal Society in 1979. Assisting Cruickshank was Meldrum’s right-hand man, Eric Porteous, a civilian draughtsman who was also involved occasionally at Fishguard.

  * The undermining of enemy positions by tunnelling and detonating explosives beneath them.

  FIVE

  PHYSICO-CHEMICAL SECTION – SABOTAGE DEVICES AND MATERIALS

  In 1941 Churchill appealed to the President of the United States with the words ‘Give us the tools and we’ll finish the job’. At the same time the Resistance groups in Europe, through their Country Sections in London, were making the same plea to SOE.

  Chapter 4 described the structure of the research and development organisation built up by SOE in the early part of the war. The following chapters describe how the tools which were developed fulfilled the operational requirements of those in the field.

  The main operational objectives assigned to SOE included the disruption of transport by rail, road and water; attacks on power supplies and communications; the sabotage of major industrial plants; destruction of major stocks of materials; and the spoiling by contamination of vital fuel, food and mineral stocks. Direct attacks on military targets were not generally considered except where SOE could provide specialist materials or expert advice. Its main involvement in paramilitary affairs was through the development of weapons dealt with in Chapter 8.

  Some way also had to be found for causing the maximum embarrassment to the German Security Forces by deflecting their attention from military activities by a variety of ‘pinprick’ diversions of varying severity. By themselves they were usually relatively trivial, but their psychological objective was aimed at undermining the enemy’s confidence and at the same time boosting the morale of the general population of occupied countries. However, those planning this kind of sabotage had to tread a cautious path between upsetting the enemy and triggering brutal retaliatory measures. Attention had to be paid to devising equipment for operations which the French called insaissible, whose perpetrators could not be readily identified.

  Many of the materials described below had applications across several types of target. They are therefore dealt with according to their broad characteristics rather than specific applications.

  Station IX had a very wide and flexible remit. In the broadest terms it was responsible for the invention and development of equipment of all kinds covering the various needs of the saboteur in the field. It did not, however, start from a completely blank sheet. As outlined in Chapters 2 and 4, in the years leading up to the creation of SOE in 1940 many of the basic needs for equipment had been foreseen in papers and pamphlets written by Grand, Holland and Gubbins. New devices to meet these needs were being developed by Section D and MI(R). SOE inherited a number of basic devices, some of which were already in production. It is interesting to record that, thanks to the foresight of Section D, when SOE was formed its agents were supplied with commercial-type detonators of German manufacture which had been obtained from South Africa before the outbreak of war.

  The work of Station IX and to some extent of Station XII was initially directed to improving many of the existing devices, and they will appear in their improved form in the following pages. A major effort was, however, devoted to the invention, development and production of novel equipment.

  To inform SOE sections of the developments being brought to fruition by the R&D Directorate, restricted publication began in November 1943 of a ‘Most Secret’ quarterly Technical Review. This dealt with: new stores and modifications to existing ones; research and wireless notes; camouflage; training and operational topics. The Research Section provided a series of ‘Laboratory Contributions’. Copy No. 88 of the first issue and No. 25 of the third issue (May 1944) of this Review have been traced. The latter also contained notes on quality control and technical literature. In the following account, reference is made to some of the material in these issues to supplement information from other sources, including personal recollections.

  To keep Operational and Training Sections abreast of developments a Demonstration Room was set up on the ground floor of the Natural History Museum in South Kensington to which senior officers had access. Later this was supplemented by the compilation of the Top Secret ‘Descriptive Catalogue of Special Devices and Supplies’ which has recently (2000) been published openly by the Public Record Office under the title Secret Agent’s Handbook of Special Devices.

  EXPLOSIVES

  In the early days, SOE depended largely on the currently available military explosives such as gun cotton, Nobel 808 and ammonal but the commercial blasting gelatine packed (by arrangement with the makers, ICI) in continental-type cartridges was also used. Meanwhile, new forms of explosive had been developed in the Research Department at Woolwich. This led to the invention of plastic explosive (PE) prepared by the incorporation of RDX in a suitable softening agent to produce a pale yellow, putty-like material which could be cut and moulded into appropriate shapes. An important property of PE was that it was both more powerful and yet safer than many other explosive materials. In particular, it could not be detonated by a rifle bullet and needed a booster charge (primer) in addition to a detonator to initiate it. Its physical nature meant that it could be dyed to imitate putty or Plasticine and carried in suitably camouflaged containers or cartons. Although it still had a detectable odour it did not, like 808, result in severe headaches. It was safe in storage – unlike compositions containing ammonium nitrate, which tended to cake under humid con
ditions: breaking up caked explosive was a very hazardous operation. The use of home-made explosives was encouraged by providing agents with recipes for making explosives from relatively easily obtainable ingredients such as potassium chlorate weedkiller and agricultural fertiliser.

  The Explosives Section under Colin Meek was to a large extent engaged in examining the use of PE in sabotage operations. Experiments led to an assessment of the appropriate quantities of explosive needed for typical operations on various targets such as metal girders, concrete and wood. Much of this was done in collaboration with Col Rheam’s Special Training School 17 at Brickendonbury near Hertford where agents were instructed in demolition techniques based in part on experimental research at Station IX. This led to guidance on the amounts of explosive needed and where it should be placed to achieve the maximum disruption and damage to machinery and industrial plant. Where details of the target had been obtained either by personal reconnaissance by an agent, from stolen drawings or from carefully analysed photographs, then special charges were designed and assembled at Stations IX and XII. Thus the charges for the most successful and most famous SOE operation, Gunnerside, were designed specifically for placement in the most vulnerable locations in the heavy water plant at Rjukan in Norway (see Chapter 15).

  SOE, through Stations IX and XII, also designed, assembled and fused the explosive charges carried by HMS Campbeltown in the St Nazaire raid of March 1942. There were undoubtedly many other operations in which the Explosives Section played a significant role but no records of them have been located.

  Also available were a series of standard made-up charges containing 1½ lb or 3 lb (0.68 or 1.36 kg) of explosive already fitted with primers and Cordtex detonating fuse. More specialised charges such as limpets and clams are described below. In many instances, however, agents made up their own charges based on the instructions given at training schools. This could under certain circumstances involve an unexpected hazard. Homemade charges were usually wrapped in rubberised fabric and sealed using the thick, black adhesive Bostik. As anyone who has tried to make up charges in this way well knows, it was almost impossible to avoid getting excess Bostik on one’s hands or clothes. This was difficult to remove completely even with the use of solvents such as benzene or carbon tetrachloride. The resultant odour, which persists for some time, and the presence of traces of Bostik under fingernails, could easily identify a bomb maker.

  It is likely that the successful SOE attack by Harry Rée’s men on the Peugeot factory at Sochaux in July 1943 depended on the use of charges prepared in accordance with training based on Station IX research, as did the destruction of twenty-two transformers which halted production at the Fives-Lille engineering works in June 1943. These were but two of nearly a hundred attacks on French industrial targets in 1943–44 listed by Foot.1

  Among the many charges designed at Station IX for specific jobs were adaptations of standard charges for cutting cables and chains below the waterline – these were probably used to cut the cables of the Italian liner Duchessa d’Aosta in Operation Postmaster. Charges for scuttling ships, demolishing gun barrels and cutting pipelines were also designed.

  The knowledge amassed at Station IX was not kept exclusively for SOE. Officers of the Explosives Section were made available to give advice to the Admiralty, Combined Operations and Auxiliary Forces, particularly on ad hoc operations where there was a specific and specialised target. The long-term research work on such topics as cavity charges, bending and cutting steel members (including rails) by explosives, cutting timber by explosives, and the effect of explosives fired underwater gave valuable scientific information to the entire military. Furthermore, the technical investigations, carried out in what were then described as ‘properly designed and equipped laboratories and magazines’, into the design of bursters, poured fillings, cast explosives, incendiary explosives, coloured explosives and booby trap devices added significantly to the sum of knowledge on these more specialised subjects.

  LIMPET MINES AND CLAMS

  Among the most widely used explosive devices were limpet mines and clams. The original limpet mines had been developed by MI(R)c. They were said to have resembled the British steel helmet of the time, no doubt giving rise to the name. They were provided with an array of magnets that allowed the mine to be attached to the side of a ship or other metal target. The SOE Mark II version consisted of a rectangular brass box measuring some 9½ × 5½ × 5½ in containing about 4½ lbs (2 kg) of explosive. The box was fitted with six magnets, three on either side. The sealing cap at one end was provided with a port threaded to take an AC fuse while an anti-disturbance fuse was fitted at the other. To enable the magnets to take up the curvature of the ship’s side they were mounted on rubber bushes. The back of the mine was fitted with a bracket which could engage with the end of a folding placing rod (also developed at Station IX) to enable the mine to be attached beyond arm’s length. Whereas the first versions were satisfactory against stationary targets (e.g. steel or iron equipment or ships in dock) their adhesion was insufficient to prevent them being washed away when the ship was underway, as Everett observed during his training at Mallaig. Improvements in the magnets were essential and this was Station IX’s main contribution. Originally they were the simple horseshoe type, but by modifying the shape it was possible to increase the area of contact. At the same time close liaison was kept through Dr Wilson with Jessops, the Sheffield company which produced the magnets and was active in developing improved magnetic alloys. Over a period of a year or so much stronger magnets were available for use on limpets. These improvements were also incorporated in magnetic holdfasts for attachment to the side of ships. In mid-1943 limpets which were attached to HMS Titania remained in place after two days at sea at speeds up to 10½ knots in rough water. Magnetic limpets were used in many operations, the most publicised of which was the ‘Cockleshell Heroes’ raid at Bordeaux in December 1942. ISRB was responsible for producing 56,000 limpets up to mid- 1945.

  The clam was a smaller version of the limpet measuring 5¾ × 2¾ × 1½ in and containing half a pound of plastic explosive. This could be used with either a Time Pencil or an L-delay inserted into a pocket in the body of the device. But it could not be used underwater. The clam was easy to conceal and, even when seen, did not attract attention. In fact, the French Section agent Harry Rée reported an incident in which a clam fell from the pocket of a member of his ‘Stockbroker’ circuit in the presence of a German soldier who handed it back to him! Some 68,000 clams were made under the supervision of Station XII.

  MOBILE LIMPETS (WELMINES)

  Limpets were originally intended to be attached to shipping targets in dock. However, when close approach to the target was operationally difficult or too dangerous, a need was seen for a limpet which could be propelled towards, and attach itself to, its target, i.e., to act as a miniature torpedo. The main problems in developing these devices required the skills of the Engineering Section which worked on the various types of Welmine described in Chapter 8.

  NAIL FIRING DEVICES

  Not all target ships (e.g. minelayers and minesweepers in Europe and junks in the Far East) were made of iron, so a requirement arose for methods of attaching Limpets to wooden, or other wet surfaces, and work on this started in December 1943. Four attempts were made to develop a quick-setting cement capable of sticking to wet wood. Only limited success was achieved, and attention was directed towards a nail-firing device. The main disadvantage was that it was noisy so that its use was only practicable where it would be muffled, possibly by the noise in a factory or dockyard, or where silence was not an important factor. Although considerable improvements were made so that it could be used on both non-magnetic sheet metal and wood it was not entirely satisfactory. Among the problems were the very variable results which were obtained with woods of different density. Further development was undertaken by SOE’s Far East Research Section (the Services Reconnaissance Department in Australia) where Capt G.I. Brown made a speciality
of devising methods of destroying Japanese-commandeered junks.

  FUSES AND SMALL MECHANISMS

  To set off an explosive it is usually necessary to use a fuse which initiates a detonator which injects a spark or small explosion into the bulk explosive. Historically, use was made of the ‘slow burning fuse’ which consisted of a thin cord impregnated with potassium nitrate. The modern version is the ‘blue touch paper’ of domestic fireworks. Over a century ago this was replaced by the Bickford fuse in which gunpowder is wound into a core of twisted hemp and coated with a waterproof material. When initiated at one end by a match, the powder burns at a roughly constant rate of about 1 cm per second until a spurt of flame is ejected at the far end into a detonator which has been inserted into the explosive. Many of the safer explosives also require an additional small intermediate booster charge (or primer) placed into the bulk explosive. The alternative is the electric detonator which is set off by an impulsive current produced by operating an ‘exploder’ connected to the charge by a wire. The mode of use of explosive charges in sabotage operations depends on the circumstances under which they are to be used. Electric detonators have the advantage that the object of attack (e.g. a train) can be kept under observation and blown up at just the right moment – a technique used, for example, by T.E. Lawrence (of Arabia). The disadvantage is that the operator has to be close to, and in sight of, the target and has to escape from the scene. The Bickford fuse introduces a time delay between lighting it and the explosion and gives the saboteur the opportunity to make a safe getaway. But there is a maximum length of fuse which can conveniently be used, beyond which delayed action devices are needed. Often it is necessary to transmit the explosion from one charge to another. This may be achieved by connecting them by a length of ‘detonating or instantaneous fuse’ burning at a rate of 88 ft per second. (Cordtex in the UK, Primacord in the USA.)