by Helen Fry
On 10 May 1940 came the news of the fall of Holland, Belgium and Luxembourg to Nazi forces. This caused ‘considerable work for MI9 and arrangements for the reception of numbers of POWs, including parachutists’,59 as fighting in the Low Countries increased the number of enemy prisoners being brought to Trent Park; most were captured in Holland. All Whitsun leave for MI9 staff, including those at Trent Park, was cancelled.60 By mid-May, it was reported that:
The fighting in the Low Countries in the last week has materially affected the activities of MI9 . . . The advent of a number of enemy POWs captured in Holland has necessitated the rapid organisation of a corps of interrogators who have been dispatched to the various ports of arrival and in conjunction with the RN and RAF have been interrogating selected enemy POWs.61
The MI9 war diary noted: ‘The agents’ house at Cockfosters has also been requisitioned.’62 Files do not name the house, but it was part of preparations to expand the secret capabilities and facilities of this aspect of MI9’s work.
Prisoners from the Norwegian Campaign were still being interrogated in June 1940 and provided detailed information on the U-boat war in the region, related in particular to two battles at Narvik, and revealing what the Germans knew about British submarines operating in the area.63
ARMY INTELLIGENCE
With much of Western Europe under Nazi occupation, Britain was next in line for invasion. Kendrick’s first survey report for 3 September 1939 to 31 December 1940 draws on information provided from only 113 German officers and other ranks.64 Prisoners captured in this period described tank battles in France prior to the evacuation of the British Expeditionary Force at Dunkirk from May to June 1940. Other conversations dealt with the type of tanks used, railway guns and the ‘liquid air’ weapon.65 Some German army prisoners spoke about the airborne assault by German troops during the invasion of Holland and the heavy losses of men and aircraft. All types and sizes of missile were mentioned, revealing that German bombs were gradually increasing in size to 3,600 kilogrammes each. In addition to high explosive devices, references were made to other special types of weaponry such as liquid air, oxygen, cable and flame bombs.66 Some prisoners expressed doubts that Germany could win the war by bombing techniques alone, thus providing an insight for British intelligence on the reality of the German military capability.
The most frequent discussions concerned a possible invasion of Britain, morale in the German forces, and the use of gas in warfare.67 As expectations of an invasion heightened, so talk of the possibility and tactics became more frequent in prisoners’ discussions, especially in July and early August, then again from mid-September to November 1940.68 Prisoners discussed the points at which the invasion would be made, the different communications to be used during it, and methods of invasion: the use of gliders, cement-strengthened barges to carry tanks, and underwater tanks and long-range guns mounted along the French coast.69 The secret listeners picked up preliminary references to a possible cancellation of Hitler’s autumn invasion plans, providing British military command with the first signs that Britain’s shores may yet be safe.70
In the period up to July 1940, the morale of the German armed forces appears to have been consistently high. Fighting morale was still defined by the belief in an early victory against Britain and that prisoners would be home by Christmas.71 As this became more unlikely, a mood of pessimism prevailed until renewed hopes of an invasion of Britain’s shores surfaced in conversations. Bugged conversations during 1940 monitored the behaviour of German troops in Nazi-occupied countries; in Belgium and Holland, German troops requisitioned whatever they could. In France, the Resistance organised acts of sabotage: captured POWs talked at Trent Park about how aircraft were damaged at night and the German telephone wires were cut; in the neighbourhood of Hitler’s headquarters, the lights went down and it was reported that 350 people were shot as a result. British intelligence learnt that French inhabitants were hiding English airmen and, according to one prisoner, ‘. . . telephone wires tapped and information transmitted to England by an espionage organisation, twenty members of which have been arrested in Brest’.72
Thirty-six Italian POWs passed through Trent Park during the period of Kendrick’s first survey, and as he himself commented, they yielded virtually no useful intelligence, except comments which revealed that they had a poor opinion of Italy’s war capabilities.73 Italian prisoners and intelligence will not be explored further in this book.
During the Battle of Britain, German prisoners’ conversations began to reveal a more general picture of the extent of German losses incurred in the heavy daylight raids and losses on night flights. In one report, a prisoner quoted Kesselring (a Field Marshal) as saying that during 1940 Germany was losing 280 aircraft a month from accidents alone. It was difficult for British military commanders to independently assess German losses from the dog-fights over enemy territory; this would require flying reconnaissance missions over those areas, but British pilots were occupied with combat and defending the country. During an air raid alarm on 2 September 1940, two prisoners at Trent Park discussed a battle overhead. Prisoner B said: ‘You can see it from here, a Spitfire up there. Just there – underneath. It has flown in a sort of arc. There it comes again over here.’74 Prisoner A replied: ‘Oh! There is a Zerstörer [More M.G. fire and roaring of engines is heard]. There it is again, the Spitfire, always following up.’
The secret listeners picked up that the Germans had tried out a type of ‘nerve gas’ with temporary soporific effect at Maastricht during the invasion of Holland in May 1940.75 Although the majority of references to gas were of a general kind, British intelligence discovered from bugged conversations that Germany would not employ gas in an attack against Britain unless Britain used it first.76 Other prisoners spoke about the alleged use of an ‘anaesthetising gas’ in Belgium.77
FRANZ VON WERRA
Germany’s flying ace Franz von Werra was captured on 5 September 1940 after his plane was shot down over Kent during the Battle of Britain. His daring escapades were later immortalised in 1957 in the British film, The One That Got Away. He was held in barracks in Maidstone for a few days, where he attempted his first escape. He was transferred to Trent Park and interrogated by Felkin, but there is no evidence that he tried to escape from there. Von Werra was found to be ‘the most optimistic of the believers in Hitler’s victory’78 and was even considered by MI9 to be ‘a completely successful product of Nazi education’.79 It was reported from his bugged conversations between 16 and 19 September 1940 that:
He approves pogroms and the beating of prisoners in concentration camps . . . Von Werra’s opinions are quoted at length for their psychological interest. His supreme confidence is exceptional.80
Von Werra was transferred from Trent Park to Grizedale Hall, a prisoner-of-war camp in Lancashire known as No.1 camp, run by Lieutenant Colonel Morton. On 7 October 1940, von Werra escaped from Grizedale Hall, was recaptured five days later and promptly sentenced to three weeks in solitary confinement at Camp No.13 in Swanwick, Derbyshire. In January 1941, he was transferred with other German prisoners of war to a camp in Canada though he again escaped and eventually made his way back to Germany. Later that year he saw active service on the Eastern Front and continued his dangerous missions. He died on 25 October 1941 after crashing into the sea, north of Vlissingen, off the Netherlands coast.
The intelligence work was demanding. Army intelligence officer Charles Deveson was one of the few to speak about it in general terms during his lifetime. His son, Richard, commented:
My father always emphasised how taxing the work was – the long hours, the need for intense concentration, the time-pressure, the often harrowing nature of the material and the unpleasantness of some of the prisoners (though others were quite reasonable).81
Born in London in 1910, Deveson had studied English at Oxford and taught at an exclusive boys’ boarding school in Prussia. He returned to England in 1936. At the outbreak of war, he was enlisted into the Ro
yal Armoured Corps but, by 1941, was transferred to the Intelligence Corps and sent to Trent Park. Kendrick asked him to sign the Official Secrets Act and then, it is said, Deveson was handed a pistol across the desk and told: ‘If you ever betray anything about this work, here is the gun with which I expect you to do the decent thing. If you don’t, I will.’82 The secrecy of Trent Park and its clandestine operation had to be protected at all costs.
Amongst his files, Charles Deveson left brief pencilled notes about his work at Trent Park, dated February 1941.83 Information was gathered by the unit on every conceivable subject, and in many cases the first indication of a new enemy weapon or device was given away in the recorded conversations. On naval matters, he listed U-boat types, tactics, names of commanders, methods of attack, torpedoes, mines (magnetic and acoustic), codes, cyphers, gunnery, human torpedoes and details of the major units of the German navy, which included the sinking of the Bismarck, Scharnhorst and Tirpitz. On military subjects, he mentioned tanks (details of new models and tank production), rockets (location of sites and description of firing ramps), very detailed information on the Gestapo, and character studies of senior officers (including Rommel and Rundstedt) and their relations with Hitler. General material was picked up for use in Black Propaganda: bomb damage, morale, atrocities, Hitler’s headquarters, and conditions in occupied countries.84
In terms of Air Intelligence, Deveson mentioned the information gathered on the Battle of Britain, air tactics, navigational methods, new kinds of aircraft, advanced information on the bombing of Coventry and Glasgow, bombs and guns, and details about night fighters.
EXPANSION OF THE M ROOM
In late 1940, plans were discussed to expand the M Room operation to two further sites in Britain.85 It was believed that Trent Park would prove inadequate for the large influx of prisoners captured in the coming campaigns of the war.86 Two estates in the heart of the Buckinghamshire countryside were considered: Latimer House near Chesham, and Wilton Park at Beaconsfield. The nearest railway station to the former was Chalfont & Latimer on the Metropolitan Line and, to the latter, Seer Green or Beaconsfield. Both sites were therefore within easy reach of London, discreet and well hidden to preserve the secrecy of the operation. A meeting took place at Latimer House in January 1941 to establish its suitability as a second site for CSDIC.87
A month later, construction work was already under way and Latimer became known as Camp 30 or No.1 Distribution Centre (No.1 DC),88 while Wilton Park became Camp 300 or No.2 Distribution Centre (No.2 DC).89 A short distance from each of the stately houses temporary prefabricated wartime buildings were constructed for CSDIC: two parallel blocks of cells, interrogation rooms, an administration block, an M Room, a block for Naval Intelligence, a cookhouse, guard block and Nissen huts were distributed within the grounds. As with Trent Park, the sites were secretly ‘wired’, with the bugging devices hidden in the light fittings of the cells and wired back to the M Room.
Latimer House and estate belonged to John Compton Cavendish, the 4th Lord Chesham. On 12 September 1939, he had entered into negotiations with New Scotland Yard for the red brick mock-Tudor house to be given over as a convalescent home for air raid casualties from the Metropolitan Police. Having been requisitioned, it was soon occupied by a unit of the Northamptonshire Yeomanry and then became the headquarters of IV Corps. Security surrounding IV Corps was paramount and Lord Chesham was required to vacate the estate. He purchased the Old Rectory opposite and moved there, but little could he foresee that he would never live in Latimer House again: at the end of the war, it was subject to a compulsory purchase order by the government for the sum of £30,000, in spite of Lord Chesham contesting the decision for five years. During 1941, the estate was vacated by all army units and construction work began.
Wilton Park in Beaconsfield, some nine miles from Latimer, was a thirteenth-century estate that once belonged to the Whelton family. It was later purchased by the Du Pre family. Josias Du Pre had carried out profitable trading through the East India Company with such success that he was able to commission the building of a large Palladian-style mansion, dubbed the ‘White House’, at Wilton Park. During the Second World War, the estate was requisitioned from Colonel William Baring Du Pre. This estate too was subject to a compulsory purchase after the war, as buildings on the site were used in the government’s denazification programme for prisoners being repatriated to Germany. The White House fell into disrepair and was demolished in 1967.
The intelligence services and Chiefs of Staff held various meetings during 1941 to discuss the expansion programme. Their conclusions survive in a series of memoranda by the Joint Intelligence Committee in Cabinet Papers.90 The memoranda were marked ‘strictly limited circulation’ and to be ‘KEPT UNDER LOCK AND KEY’ because they were highly classified. The intelligence chiefs concluded that the unit was:
Of the utmost operational importance, vital to the needs of the three fighting services and should accordingly be given the highest degree of priority in all its requirements, that the normal formalities regarding surveys, plans and tenders should be waived and that any work required should be put in hand at once and completed by the earliest possible date irrespective of cost.91
Amongst the signatories of this recommendation to the Joint Intelligence Committee were Stewart Menzies (‘C’), John Godfrey (head of NID) and Francis Davidson (DMI). The Joint Intelligence Committee approved the request and Kendrick did not need to go through the usual channels for authorisation.92 The priority of extending the bugging operation was underlined by John Godfrey when he reported: ‘I regard this as of such importance as to override normal considerations of cost and I hope that you will be able to use every endeavour to see that this expansion is given absolute priority.’93
Godfrey’s counterpart at the Air Ministry, Archibald Boyle, wrote to the Director of Military Intelligence, Major General Francis Davidson, on 19 December 1940:
The value of the information obtained has been inestimable, and at all costs must continue to be obtained to the fullest possible extent. I want to emphasise how important it is from the Air point of view, for nothing to stand in the way of the development of this Centre to a maximum output in a minimum space of time.94
A memorandum that survives in Cabinet Offices files indicates that unlimited funds had been authorised for this expansion to two new sites.95 To make the sites operational was estimated at a cost of over £400,000 (equivalent to around £25 million today).96 Clearly, funding of that level would not be released to a unit that was speculative or might not have produced results. This intelligence unit was considered indispensable for the war and was not therefore to be restricted by a lack of funds.
However, a problem soon arose: two new aerodromes were in the process of being constructed near Wilton Park and at Bovingdon, just three miles from Latimer House. Kendrick wrote to Crockatt (head of MI9) explaining the issues:
If an aeroplane passes in the vicinity of the house, even at an appreciable height, M Room operation is momentarily blacked out. This has occurred in a number of cases when conversations on subjects of primary importance were being recorded. The loss of a phrase or a significant word may render unintelligible some vital source of information.97
Kendrick’s concern was discussed at a meeting of the Joint Intelligence Committee.98 Intelligence chiefs agreed that construction of the aerodrome at Wilton Park had to be cancelled. Bovingdon aerodrome was already sixty per cent completed at a cost of £300,000, and so to minimise interference with Latimer, it was downgraded to a ground training station for Bomber Command, with flying restrictions in place.99
JUSTIFYING THE M ROOM
Norman Crockatt wrote in his evaluation report: ‘The regular and continuous supply of SR and SP reports . . . provides accurate and completely untendentious information on the general topics outlined. Providing a regular supply is maintained, these methods produce better results than would intensive direct interrogation of POWs who have already been subjected to th
is by Navy and/or Air Force.’100
Kendrick circulated a questionnaire to various departments of military intelligence asking whether the information obtained from the bugged conversations was of relevance or important to that department. MI6 stated that the interrogation reports and Special Reports were ‘of considerable importance and their method of presentation is excellent’.101 MI14, which specialised in intelligence about Germany, replied that they were:
. . . of vital importance in connection with enemy preparations for combined operations. It is of importance in adding to our records of personalities, Field Post Numbers, locations . . . concerning enemy morale, the German scene, relations between party and the army, political opinions, etc. In this connection these reports are frequently of considerable interest in so far as they provide possible material for the broadcasts to the German army.
Moreover, the German text of the conversations was of special value ‘in certain cases where the English text unavoidably leaves a doubt in the reader’s mind as to the exact shade of meaning’.102
The Air Ministry provided guidance on the kind of information it needed from the M Room and what topics the secret listeners should record. The topics of interest to the Air Ministry included knowledge of tactics of German air force bomber and reconnaissance pilots by night and day, heights at which they attacked targets, routes most frequently used and methods of identifying targets, use made of beams, and flak.
A reply from the Political Intelligence Department (Foreign Office) highlighted the importance of M Room intelligence for propaganda purposes, especially for information which they could not obtain any other way: ‘These reports are our only first-hand information concerning the state of mind of the clients for our propaganda.’ It went on to say that, ‘the present dialogue form of SR reports is of greater value, but in order to conceal the method by which these reports are obtained we are glad to have the summarized intelligence reports as it enables us safely to give them a slightly wider, though still restricted circulation.’103
