Codeword Overlord

by Nigel West

  If they did this they could say that they were fulfilling their promise to Russia and if they succeeded they could then attempt a full-fledged expedition over … the English Channel.

  The intercepts were given very limited circulation in Whitehall as BLACK JUMBOs or ‘BJs’, and in the United States as MAGIC, and would occasionally offer unrivalled insight into confidential briefings given by the Reich to its Axis partners. Intercepts from his military attaché, General Osamu, were also read, and designated JMA (for Japanese Military Attaché), reflecting the views of the attaché staff, which amounted to fourteen in all. Additional, equally helpful, traffic was intercepted to and from the Japanese military attaché in Vichy.

  On 24 April Oshima informed Tokyo that ‘in regard to the Anglo-American invasion, there is strong expectation that it will take place during the present week; however, if it does not, that will indicate that it may be delayed for several weeks.’ On 27 April he reported, ‘everyone has a deepening conviction that the Second Front is almost here and a tense atmosphere can be detected in the articles of the press’. However, on 6 May he conceded that the time for the expected event had ‘passed, there is now a strong body of opinion that operations in question will be postponed another two or three weeks’.

  Oshima, who spoke fluent German and held the rank of lieutenant-general, was especially trusted by Hitler, who received him at the Berghof on 27 May. He was granted an audience lasting two hours, which resulted in a lengthy, seven-part telegram to Tokyo setting out the Führer’s private prediction. The full text of Oshima’s message was quickly circulated by Bletchley Park, as summarised by Guy Liddell:

  On the 27 May Hitler, when speaking to the Japanese ambassador said that he himself thought that after having carried out diversionary operations in Norway, Denmark, the southern part of the west coast of France, and the French Mediterranean, the allies would establish a bridgehead in Normandy and Brittany and after seeing how things went would then embark on the establishment of a real second front in the channel. If this is the firm view of the German General Staff it is not altogether discouraging since they evidently expect that our first effort will be a diversion. They do, however, seem to think that the main attack will be dependent to some extent on the success or failure of the establishment of the bridgehead in Normandy or Brittany. This might, therefore, lead them to make an allout attack on the bridgehead at once. If however, they think that the main attack is coming across the narrows, they should at least maintain considerable reserves, and the firmer the establishment of the bridgehead the more inclined they should be to withhold these reserves. GARBO’s whole plan is not to speculate on the actual target but to build up the idea that the first attack will be a diversionary one and that reserves are being kept for the main drive. Meanwhile, we have destroyed, two or three days ago, the principal bridges over the Seine. This should leave the Germans in doubt whether we intend to attack north or south of the river. They may, of course, think that this is a somewhat early manoeuvre and merely a blind. Meanwhile, the 21st Army Group are getting rather nervous about the number of divisions moved into the area south of the river and are suggesting that we should put over some hot deception to get them out of the area. My own view, and T.A. Robertson’s, is that we should continue as we are. It is extremely doubtful whether anything we could do, unless we were prepared to blow all our agents, would have any material effect at this juncture. GARBO’s build-up is more likely to be effective after D-Day.

  Hitler claims that the output of fighters, which may include every type, fast bombers and dive bombers, should be 6,000 a month by September and 8,000 a month by January 1945. This is probably a very exaggerated estimate in order to impress the Japanese.

  A captured map, issued by FHW on 15 May, calculated the Allied strength available for an invasion at fifty-six infantry divisions, seven airborne divisions, fifteen armoured divisions, five independent infantry brigades, fourteen tank regiments and eight parachute battalions. Significantly, the map placed large concentrations of US troops in East Anglia and south-east England. Another map, dated 20 May and issued by the Luftwaffe’s II Fliegerkorps, appeared to mirror these inflated figures, and also grouped the US First and Ninth Armies as part of FUSAG, while omitting 21st Army Group and the Third US Army altogether.

  Naturally, while the Germans debated on what to expect in the coming offensive, British analysts studied what evidence was available of the German deliberations. SIGINT played the key role in this, although the very existence of BJs would remain a closely guarded secret for many years, and not even hinted at in Roger Hesketh’s post-war official history of FORTITUDE. Although MI5, LCS and Ops (B) were avid consumers of any relevant intelligence available, the epicentre of the customer class was the Joint Intelligence Committee (JIC), which reviewed the evidence and distributed summaries to a limited list of authorised recipients, without citing specific sources. Thus, on 1 March 1944 the JIC had issued ‘German Plans and Intentions During the First Half of 1944, with Particular Reference to OVERLORD’, which had declared that:

  Germany is aware that Allied forces are rapidly being built up in the United Kingdom and there is some evidence that at present she expects the main attack will be made against the coastline facing the English Channel.

  By 22 May, when the JIC produced a paper entitled ‘German Appreciation of Allied Intentions Regarding OVERLORD’, it confidently declared that:

  The main assault is expected against the northern coast of France from Boulogne to Cherbourg inclusive. Although the German High Command will, until our assault takes place, reckon with the possibility that it will come across the narrow Straits of Dover to the Pas de Calais area, there is some evidence that the Le Havre-Cherbourg are, including as it does those two first class ports, is regarded as a likely, and perhaps even the main, point of assault.

  On 3 June the JIC weekly assessment reassured its readers that ‘there has been no evidence … to suggest that the enemy has accurately assessed the area in which our main assault is to be made’ and observed that the enemy ‘appears to expect several landings between the Pas de Calais and Cherbourg’.

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  On 19 March 1945, following the occupation of Remagen, a Wehrmacht officer, Oberleutnant Dr Helmut Arntz, surrendered to the US First Army and revealed that until recently he had served as adjutant to General Albert Praun, the OKW’s chief signals officer. More importantly, Arntz disclosed that he had accumulated a large cache of secret documents hidden in suitcases buried in his garden, and among them were a series of FHW intelligence assessments that made fascinating reading for the SHAEF (Ops B) staff.

  Arntz remained in American custody for two years, and gave a detailed account of his pre-war academic career as a philologist at Giessen University that, he claimed, had been curtailed because of his Jewish grandmother. During his service with Praun he had retained various OKW documents he considered historically significant, but had been implicated in the 20 July plot. Among the papers was the FHW’s ‘Survey of the British Empire No. 28’, dated 29 April 1944, which referred to the non-existent British 58th Infantry Division and to the very authentic landing ship Bulolo, which had participated in the TORCH and HUSKY landings in the Mediterranean:

  Great Britain and North Ireland

  The total number of employable British–American units in Great Britain and North Ireland has increased since the middle of April by two British Infantry Divisions up to now believed to have been in the eastern Mediterranean area, one British Armored Brigade from Iceland, and also by one American infantry division from Iceland, and thus at present probably amounts to about 54 Infantry Divisions, 2 Independent Infantry Brigades, 7 Airborne Divisions, 8 Parachute Battalions, 14 Armored Divisions and 14 Armored Brigades.

  By the end of April the army and air force units assembled in Great Britain were ready to jump off. There is still only incomplete information available as to the shipping space. However, increased reconnaissance along the English Southern Coast indi
cated that focal points are appearing in this area, one at Portsmouth, the other at Dartmouth–Salcombe. It must, therefore be assumed that operations for shipping space at the principal ports of departure along the English south coast are in full progress or have been completed.

  A great number of individual observations point towards the beginning of operations in the near future. The following are particularly noteworthy:

  1. The directive of the British government under which the diplomatic representatives of neutral nations and of several Allies are authorized only censored postal traffic with their countries and are prohibited from leaving England.

  2. The cessation of air mail service to most of the European countries and to British PoWs.

  3. The air force manoeuvre taking place in southern England which will apparently be used to camouflage troop movements.

  4. The continuous transfer of radio stations of the British tactical air force units from the area north and south of London to the Brighton, Portsmouth, Southampton area, with parts also in the area west of Dover.

  5. The identification of the British flagship Bulolo in the Portsmouth area. This flagship played a role in all the landing operations in the Mediterranean.

  6. The extensive restrictions in civilian travel in Great Britain.

  7. The recent requisition of numerous public buildings for hospitals and the drafting of a great number of nurses.

  The British–American air attacks against the occupied western areas, which extend mainly to the ground organization of the Luftwaffe and main traffic centers as far as the western area of Germany increased again during the second part of April. According to enemy statements, they not only constitute the preparation but are already the first phase of the invasion.

  The observation of liaison between the British tactical air force units with parts of the airborne units concentrated around Salisbury (towing and transport units) point towards an intended employment of airborne divisions against northern France.

  1. Order of Battle

  According to a British official source, there is a British Army Group in Great Britain. This is probably the British Army Group under the command of General Sir Bernard L. Montgomery, whose number had been unknown up to now.

  Anti-Semitic demonstrations occurred among the Polish troops stationed in Great Britain, which caused several hundred Polish Jews to desert and to request to be taken over into British units.

  (a). Scottish Command.

  An Abwehr source, which has been accurate in the past, was able to identify the organization of forces in Scottish command. This showed that the number of British–American divisions believed to be in this area should be increased by two infantry divisions.

  The detailed picture is as follows:

  Between Edinburgh and Stirling, there is the 58th British infantry division (mot.). This unit, which in the fall of 1943 was moved from Italy to Syria and which had been confirmed there several times, was transferred about New Year from that area to Great Britain, and is now probably under the British II Corps.

  In the same area there is the British 58th Infantry Division, which up to now was believed to be west of London in the area of Service Command South. Since there has been no confirmation of the presence of the division in that area, it must be supposed to have been transferred into Scottish Command at the beginning of this year as had been reported. [Report incomplete]

  Arntz also provided a copy of a FHW teletyped weekly situation report for the period 15 to 22 May 1944, dated 23 May 1944:

  1. Enemy Situation

  A. West Coast Front

  Enemy air activity during period covered by report was at first handicapped by poor weather in the English jump-off area. Only near the end of the period were operational conditions again more favourable. For these reasons there were only two days of heavy enemy air activity in the area of C. in C. West with attacks by 2 and 4 motored units in considerable force against railway installations in Belgium, the area north and south of the Seine (the latter at night) and against airports in the Paris and Reims areas causing considerable damage in some places.

  19 May: In the late afternoon, as the result of improved weather, the enemy resumed attacks against coastal defence installations of all types (small independent fortifications, batteries, radar and air warning service installations) in the area between Calais and Cherbourg.

  During the period from 15 to 21 May, 53 strongpoints (battery positions, resistance nests) were attacked in this area. As a result, 4 fortified positions, of which 2 were slotted positions, were slightly damaged but remained in combat condition; 4 reinforced field positions were destroyed, 11 damaged; 10 field positions were destroyed and 15 damaged. Of the heavy weapons (guns and coastal defense guns) 11 were knocked out temporarily, none were destroyed permanently. The losses in personnel of the MLR during the same period amounted to 28 killed, 13 missing, and 93 wounded.

  The maximum commitment in the area of C. in C. West on 19 and 20 May amounted to 4,500 enemy planes, of which a considerable number were employed against coastal defences. In comparison to the size of the operation, damage and losses were again very small. During the nights of 16 to 17 May and 17 to 18 May enemy planes made definite attempts against offshore obstacles north-east of Calais and at the mouth of the Seine, respectively. During this operation, two British army officers were captured. According to testimony, this reconnaissance is supposed to have been taking place for some time along the Dutch coast to and including Normandy. The reconnaissance mission probably also includes reconnaissance of land minefields containing new types of mines. It must be assumed that the enemy is informed at least about the earlier types of offshore obstacles. Reconnaissance activities are proof of the continued invasion preparations. Supply flights and mining activity remained relatively insignificant and the activities of light enemy naval forces also were smaller than in the previous week. Strong enemy naval guards (2 destroyers, 3 to 4 minesweeper units in the Channel between Lyme Bay and the Channel Islands). Convoy traffic according to plan. The movement of landing craft to the south-eastern English ports continues. No photo air reconnaissance during the period covered by this report. No new results through visual reconnaissance. Signal monitoring continues to indicate much manoeuvre activity; otherwise regular radio traffic. Prisoners from the Canadian destroyer Athabuscan confirmed the air photo reconnaissance of the port of Plymouth, French battleships were supposedly converted into training ships and are therefore not fit for battle. Agents’ reports, besides a wealth of new landing dates, some of which have passed already, express the belief that there will be no large-scale offensive on a broad front, but at first the emphasis will be only on the formation of bridgeheads.

  C-in-C West makes the following appreciation of the situation: Focal point of the enemy invasion concentration lies in South and South-east England. The area around the Isle of Wight (Portsmouth–Southampton) is a focal point of the preparations. Without any doubt, the Channel coast between the Scheldt and Normandy, and the northern part of Brittany, including Brest, remains the endangered main front. The target areas of the enemy air force against the coastal defenses, the traffic installations and the airports correspond with this. Enemy air activity, so far, has been greatly disturbing and has been a great handicap to traffic, but there is still no last systematic preparation for a large-scale attack. The latter depends upon the developments in the overall situation (Italy, East) and consistently favorable weather. It is probable that the enemy will use new types of weapons in the landing, perhaps even gas. The men will be prepared for this. Every day of delay in the attack means the strengthening of our defenses.

  B Mediterranean Coast Front

  Appearance of enemy submarines in the western part of the Gulf of Lyon is confirmed by the torpedoing of a ship off the port of Vendres. Enemy submarine for the first time off La Cictat. On 10 May bombing and strafing attack by several planes against the Navy signal station at Cape Camaret. Only slight damage; no losses. Passage o
f a USA convoy probably to the Indian theater or for the formation of operational reserves in the Eastern Mediterranean. Movement to Corsica of tactical airforce units whose CPs and ground organization had been monitored, could not as yet be confirmed by visual or air photo reconnaissance. Ship concentrations in African or south Italian ports for the purpose of a large-scale leapfrog landing along the Italian coast or for landing operations on the French south coast could not be observed as yet.