The Walls Have Ears

by Helen Fry

  The transcripts occasionally provide details of daily life. Three U-boat prisoners were overheard telling each other not to give anything away to the British in interrogation.5 One of them, designated N209, was security-conscious and told his mates: ‘We have a microphone in our room, built in above the fireplace. I unscrewed the lid. Up to now I’ve been in room B.1. There is an aviator in the room opposite. He is a W/T [wireless transmissions] operator called A40. An air force officer keeps visiting him and talks to him by the hour.’6 N210 signalled his name through to N184 by tapping on the wall. The transcript then notes that N184 said to him: ‘N210 come close to the wall and try to talk. Do you hear me?. . . Did you tell anything about our boat? [silence] That’s too hot. They have a microphone in here after all.’ (Begins to knock on the walls to find the microphone.) Guard enters: ‘Did you knock?’ N184 replied to the guard: ‘Yes, I want to go to the lavatory.’ He is taken to the toilet and on his return resumed his conversation through the wall, discussing how there were thirty experienced U-boat officers in the camp.7

  The discovery of microphones was rare, but if a prisoner was known to have found one or was actively looking for bugging devices, he was swiftly transferred away to another camp.8

  Up until the end of December 1940, 685 German airmen were brought to Trent Park.9 What they provided was contained in over a thousand reports and often related to technology aboard their aircraft: ‘It can be said without fear of contradiction that there was hardly an aircraft, an aircraft engine, bomb or piece of aircraft armament which was not known by ADI(K) through the interrogation of prisoners, often a considerable time before the emergence of such a weapon in operations.’10

  Luftwaffe pilots talked about their respect for the British Spitfire which was holding its own in the skies over England. The following extract comes from a recorded conversation between a wireless operator (A26) and a pilot (A29).

  A26: The Spitfire overtakes us.

  A29: A first class machine! What a pity we haven’t one like her.

  A26: She has better manoeuvrability and . . .

  A29: (interrupting) Goes faster?

  A26: Yes . . .

  A29: If the Spitfire goes up to 10,000 metres, or even 9,000 metres, the fighters will not catch up so easily; even the 109 will find it difficult enough.11

  Luftwaffe pilots now pinned their hopes on Germany’s new Focke-Wulf fighter which was expected to go into action shortly. In the same conversation, pilot A29 admitted to A26 that he had flown the new Focke-Wulf fighter. A26 then commented that there was another new machine. To which pilot A29 replied: ‘The HE177 dive bomber; it is to go to the formation that I was to join. But they [the British] mustn’t find out anything about it and we mustn’t talk about it in camp. It is still being kept dark, even in Germany.’12 The following was overheard about the Spitfire and Luftwaffe formations for attack on coastal cities and docks:

  A344: The Spitfire is better at banking than the ‘110’. Our W/T operator only has four weapons in the moveable turret. He can’t shoot straight in front. The Air Force has equipped the ‘109’ with bombs. It is a marvellous idea and works quite splendidly. During the attack we flew in Staffel formations. One Staffel always flies 2,000 metres lower than the other. We set fire to all the oil stores in Portland, Weymouth and Plymouth. They shot down six of us.13

  A comment made by a Luftwaffe pilot to his cellmate on 28 March 1940 revealed: ‘The whole of North Germany is one big aerodrome. The further north one goes, the worse it becomes.’14

  Major General Francis H. Davidson (the new director of Military Intelligence) commented on Kendrick’s first report: ‘I have inspected the whole show and thought it very efficiently run: and the general spirit of this Survey (and the weekly reports) shows the true spirit of attacking intelligence.’15

  BATTLE OF THE BOFFINS

  In the spring of 1940, the operations at Trent Park discovered new technology being used by the German air force – Knickebein, X-Gerät and Y-Gerät – which, according to Felkin, had far-reaching consequences.16 Knickebein made use of a radio navigation system developed for civil aircraft for use in bad visibility, broadcasting two adjoining radio beams in line with a runway.17 If the plane was to one side of the runway line the pilot would hear ‘dot’ pips in his headphones, if on the other he would hear ‘dashes’, and when they merged into a single unbroken tone, he would know that he was approaching along the centre line of the runway. In the bombing aid system, two such guide beams were sent from widely spaced transmitters, aimed to cross over the target. The bomber flew along one guide beam, and when the other beam signal could be heard (on another receiver) the pilot knew he was over the target. The British did everything possible to jam Knickebein and render it ineffective.18

  X-Gerät, the new Y beam technology fitted to Luftwaffe planes, was developed when the British became too good at interfering with Knickebein. It functioned like an early radar system enabling pilots to conduct more precise bombing raids across England:19 the bomber flew along a main guide beam, intersected by cross signals set at specific distances from each other and from the target. On getting the signal from the first intersecting beam, a timer was started. On crossing the second, a further impulse would be fed into the timer. As the distance between the intersecting beams was known, this showed the ground speed of the aircraft irrespective of headwind or tailwind, so at the moment the bomber reached the target (again at a known distance from the second intersecting beam) the timer automatically released the bombs.

  An early reference to X-Gerät was recorded in February 1940 between a Lance Corporal (A35) and a Wireless Operator (A38). A35 commented to A38:

  They [the British] have just shot down a machine in which an X-Gerät is installed and they can try it out as much as they like, for it is so secret that only he knows about it, or the crew knows it and if the crew keeps its mouth shut they’ll never find it out. They can try it out and examine it as much as they like. It is a sort of apparatus that they will never find out.20

  Twenty-eight-year-old scientist, Professor Reginald Victor (R.V.) Jones was engaged as head of the Scientific Section of MI6. Working from his office at MI6 headquarters at 54 Broadway, he was to advise on the technical intelligence being gathered at Trent Park.21 He also became a key scientific advisor to Churchill and the Cabinet on X-Gerät, Knickebein, and eventually V weapons, after Churchill became Prime Minister in May 1940.22

  The significance of the discovery of this technology cannot be overstated. It provided British intelligence with knowledge of new technology being used by the Luftwaffe in sufficient time for ‘the British authorities to prepare countermeasures against a method of bombing which in the autumn of 1940 constituted a very real threat to British War Industries.’23

  On 10 April 1940, Kendrick received a glowing letter from Norman Crockatt (head of MI9) about the discovery of X-Gerät, with congratulations to ‘those officers under you who contributed so largely to one of the most successful pieces of intelligence investigation I have ever come across.’24 Crockatt later reported: ‘The secret recordings produced some of the earliest information of the German experiments in Air Navigational aids (March 1940), and has played an important part in the successful development of the British counter-measures.’25

  A German bomber pilot (A807) told another pilot (A777) that the British interrogation officer already knew that two beams were sent out from a base in Cherbourg, but nothing more detailed than that. Pilot A777 replied: ‘They know that all the construction work is carried out by the French. He has a rough idea of it, but he doesn’t know exactly, especially about the new Y-Gerät.’26

  The prisoner had just unsuspectingly given away the existence of Y-Gerät which the Germans had devised to overcome English interference in earlier technology. It was harder to jam than a system of cross beams, allowing ground controllers to determine the position of the bomber by measuring time delay of responding (reflecting) signals from the aircraft, giving distance from the ground
station and instructing the pilot by radio.27 For bombing purposes, Y-Gerät was claimed to be accurate to within an area of 200 square yards. The prisoners did not appear to know the precise location of the beam transmitters, but they did know that there were two positions: Zentrale A and Zentrale B. ‘A’ was west of Cherbourg and ‘B’ in the neighbourhood of Kassel. Once British intelligence knew the location of these transmitters, the information was passed to the RAF which authorised air sorties to attack the transmitters. Although a map of the system had been captured by the British, it was barely legible. It was only from the bugged conversations that British intelligence was able to reconstruct most of the beam lines of the Y-system.

  The Y-system operated from Kassel to Hull, Sheffield, Liverpool, Birmingham and London, and from a point just west of Cherbourg to London and Sheffield. At least four tracks were drawn from Poix and at least seven from Fécamp. This system was effective for the Luftwaffe until the British learned to transmit false ‘reflecting’ signals from Alexandra Palace in North London. Within a year, all German aircraft had been equipped for the Y-system but prisoners were still talking about Knickebein.28

  NAVAL INTELLIGENCE SECTION

  In 1940, British warships and submarines battled hard for supremacy at sea. Losses from attacks by the German navy and U-boats inflicted serious damage on the Royal Navy, merchant shipping and supply lines into Britain. It was a difficult battle that would last most of the war. During the period of Kendrick’s first survey to the end of 1940, 447 German naval officers and 31 Italian naval officers passed through Trent Park. They comprised survivors from thirteen U-boats and one armed German trawler.29

  Italian naval POWs provided very little by way of information, except to give an indication of low morale amongst their crews. The German POWs, on the other hand, yielded the most valuable intelligence. From their conversations, British intelligence established details of the strength and movement of German U-boats and their losses during the Norwegian campaign, and monitored the progress of Germany’s new battleship construction programme.30

  On technical matters, the most important naval information for this period was the discovery of the new magnetically-fused torpedo.31 Some of the prisoners spoke about it in detail. In simple terms, it could be fired from a U-boat and explode underneath a British ship as soon as it detected the magnetic field from that ship. The Admiralty had already added a degaussing coil to its ships to de-magnetise them as protection against German magnetic mines lying on the sea bed. To counter the new threat from magnetically-fused torpedoes, the Admiralty added extra degaussing coils. This was done in sufficient time before the Germans had the chance to use them effectively in action and is one example of how intelligence from the M Room about new technology had a direct impact on the Battle of the Atlantic.

  On 12 March 1940, Burton Scott Rivers Cope joined the Naval Intelligence section at Trent Park.32 His grandson, Derek Nudd comments: ‘It was the nature of the job that he left few footprints.’33 Burton Cope, born to English parents in Munich in 1885, was a fluent German speaker and had served in Naval Intelligence in the First World War. In the inter-war years, he worked abroad for Cunard White Star Lines and was living in Paris with his Swiss wife Marie Louise Girard and young daughter when the Second World War broke out. They returned to London and Cope was sent to Trent Park where the small Naval Intelligence section then comprised the interrogators Lieutenant Colonel Bernard Trench, Lieutenant Commander Edward Croghan, Lieutenants Richard Pennell and Wilfred Samuel, all of whom already had at least two months experience of interrogation at Trent Park before Cope arrived.34 Lieutenant Commander Philip Wood Rhodes was engaged in liaison between the Director of Naval Intelligence and MI9. By the end of the year, they had been joined by Sub-Lieutenant Dick (Richard) Weatherby and Miss E.R. Heath (civilian assistant).

  From April 1940, letters to and from naval POWs went via the Naval Intelligence section at Cockfosters for censorship.35 The censor discovered that the prisoners were coding their letters to Germany but, as the codes had already been broken by the British, they were allowed to go through as British intelligence wanted to see the coded replies from Germany.36 The letters revealed precise attempts by Germany to deliberately plant trained POWs amongst the ordinary prisoners to instruct them in methods of cooperation with airborne troops when Germany began the invasion of Britain.37

  The Naval Intelligence section at Trent Park expanded the following year.38 It included Ralph Izzard, formerly of the Daily Mail newspaper, as an interrogator.39 After D-Day, Izzard served in liberated Europe with Ian Fleming’s 30 Assault Unit, a special commando unit that raided Germany and its occupied territories to obtain its new technology, equipment, documentation, scientists and technologists in a race before they fell into Russian hands.40 Izzard is said to have provided the inspiration for a scene in Fleming’s Bond novel, Casino Royale.

  The female team were Evelyn Barron, Jean Flower, Claudia Furneaux, Esme Mackenzie, Gwen Neal-Wall, Celia Thomas and Petty Officer Ruth Hales.41 The WRNS spoke fluent German and knew as much about the German navy as the male interrogators.42 In a rare interview, Evelyn Barron revealed the work of the female team: ‘We did not do translation work, we were the interrogators. The German prisoners found it most unnerving to be interrogated by a woman!’43 Apart from CSDIC Cairo and one female interrogator with MI9 at Wilton Park, the Naval Intelligence section is the only unit known to have used female interrogators in the Second World War. Their insight and analytical skills in processing the intelligence gained from prisoners improved the work of the unit. Furneaux was also known to have accompanied U-boat officers on a pub-crawl in London, as a reward for their cooperative behaviour.44 The naval section was soon joined by Brian Connell, who was fluent in four languages, Czech refugee Harry Scholar, and Charles Wheeler, a young officer in the Royal Marines.45 Colin McFadyean, an idealist, fluent in German and French, had been appointed in September 1939 by Ian Fleming to head the German section in Naval Intelligence;46 he joined the team at Trent Park in March 1942.47

  Donald Burkewood Welbourn joined the Naval Intelligence team as an interrogator on the personal recommendation of Commander Cyril Francis Tower (the officer in charge of the German section).48 When a U-boat crew arrived at CSDIC, they were first stripped, searched and given a bath. Welbourn commented:

  They were often in need of clean clothes, since the stench of the typical leather clothing of U-boat crew, compounded of sweat, diesel oil and many other things, has a pungency which does not commend itself. An interrogator would be present, since a lot could be learned at this stage; nothing but German coins in the pockets suggested a boat straight from Germany. Letters from home, condoms, notebooks, all added scraps of information about the man and his boat.49

  Once the crews had been given clean clothes and civilian rations, they were put in a cell with another mate. A little later, they were interrogated. The time between first arriving in the cell and their interrogation was a crucial period when M Room operators listened into the conversations for idle chatter. This careless talk gave the interrogators a head start. ‘If, when a man came in for interrogation,’ commented Welbourn, ‘we could start by giving him the number, and sometimes the nickname of his boat, with the captain’s name, his base and a pretty good description of where she had been before, he might think that we already knew so much that the effort of not talking was not worthwhile.’

  THE NORWEGIAN CAMPAIGN

  On 9 April 1940, Norway and Denmark were overrun by German forces. Between 9 April and 10 June 1940, in what is known as the Norwegian Campaign, British forces sought to repel German troops with the aid of French and Finnish resistance fighters. Although there was some success at Narvik (northern Norway) with heavy losses inflicted on the U-boats and German destroyers, the campaign ended in military failure for the Allies and marked the beginning of six years of German occupation of Norway.50 The sinking of the British battlecruiser HMS Glorious off Norway in June 1940, with the loss of over 1,200 me
n, was one of the biggest naval disasters of the war.

  In spite of the overwhelming losses, some enemy POWs were captured during the Norwegian campaign. They were brought back to Trent Park, interrogated by Trench, Croghan, Samuel and Pennell,51 and their subsequent conversations were bugged.52 Amongst them were survivors of U-49 which had been sunk near the port of Harstad (Norway) on 15 April 1940. At the end of April, steps were taken to increase the number of interrogators at Trent Park to cope with the work expected following the capture of POWs from the Norwegian campaign.53 Captain Steege, Lieutenant Hornby, Lieutenant Jeune and Lieutenant Burrows were added to the team of army interrogators.54 They were trained by Captain Alexander Scotland (Intelligence Corps and MI9), an expert in the interrogation of German POWs during the First World War.55 In early 1940, he was based at Cockfosters56 in a small interrogation quarter at Ludgrove Hall – a small country house in Games Road, and once part of the Trent Park estate.57

  The new interrogators were dispatched to various ports around Britain, attached to the RAF and Royal Navy, to interrogate selected POWs for MI9. The MI9 war diary noted: ‘The operations in Norway have resulted in considerable increase in the activities of MI9(a). Much useful information has been received from this source.’58 There is no elaboration on the kind of information gained.