Before tracing the further progress of physical deception as directed by the Joint Commanders’ Plan, something must be said about Exercise FABIUS and its influence on the operation. This full dress rehearsal, in which four assault divisions and their associated naval forces were engaged, took place in the English Channel during the first week of May and was based on Southampton and the neighbouring ports. The total concealment of an exercise of such vast dimensions was too much to hope for. The wireless programme was therefore arranged, on the one hand, to preserve such well-guarded secrets as the hour of the assault and the landing of tanks before infantry, and on the other, to make the general pattern of the wireless traffic resemble as closely as possible that which would be audible at the time of the real attack, so that FABIUS could be presented as the first and OVERLORD as the second of a series of amphibious exercises.1 In order to support this interpretation of events, the Prime Minister, at the request of General Eisenhower, had included in a speech which he broadcast on 27th March, the following passage: ‘And here I must warn you that in order to deceive aid baffle the enemy as well as to exercise the forces, there will be many false alarms, many feints and many dress rehearsals.’
In certain respects the cover operation received some positive assistance from FABIUS. The invasion fleet was in fact divided into two task forces, the Eastern under British and the Western under American command. The wireless networks of these forces were dissociated in order to give the impression of two independent operations. Furthermore, certain wireless links controlled by the Admiralty were so arranged as to give a bias towards the East, these links continuing to operate after the exercise had ended.
At all times wireless provided the foundation for FORTITUDE SOUTH in its physical aspect. As recorded in a previous chapter, the network representing the land forces had already begun to operate on 24th April. To give further emphasis to the south-east coast, the wireless traffic of the Combined Headquarters at Dover and Chatham was increased in volume, and new links were introduced in order that these stations might resemble the Combined Headquarters at Portsmouth as closely as possible.
Arrangements now had to be made for the inclusion of amphibious training in the deceptive wireless programme. In this respect the Southern operation presented greater difficulties than had been experienced in Scotland. The danger of aerial reconnaissance over Loch Fyne had been comparatively remote, but this could not be said of the south or south-east coast of England. In order to give a reasonable time for assault training, it was necessary that the exercises should begin in April. But at that time none of the dummy craft was ready. For this reason it was decided to start by using a real naval assault force. Accordingly, at the middle of April, the 4th Infantry Brigade of the 2nd Canadian Division, one of FUSAG’s assault formations, was represented as being at Studland training with Force ‘G’. The reasons for choosing Force ‘G’ were, first, that it was newly formed and therefore not firmly linked with any particular military formation, and, second, that the division with which it had been training was British and therefore the addition of a Canadian brigade would be noticeable.
On 20th May the launching of the dummy craft began and by 12th June two hundred and fifty-five2 were displayed at various points on the east and south-east coasts from Great Yarmouth to Folkestone.
At the same time, the CLH units provided suitable wireless traffic on an increasing scale until, by degrees, the semblance of a new assault force had been created. This became known as the Imaginary Force ‘F’. Early in June the 28th United States Infantry Division left its fictitious location in Kent for a fortnight’s training with Force ‘F’ at Felixstowe. In order to add realism, on 8th June the headquarters ship HMS Lothian was ordered to Harwich. The subsequent vicissitudes of Force ‘F’ will be considered later.
QUICKSILVER IV, which called for a deceptive bombing programme on the Pas de Calais, was not conducted as a separate operation. The real operations of the Allied air forces were, however, so adjusted as to focus attention on the false objective.3 Before the invasion, for example, forty-nine airfields within a radius of 150 miles of Caen were attacked, of which eleven were in the Pas de Calais and four in the NEPTUNE area. During the same period nineteen railway junctions supplying the Pas de Calais were attacked, while no junction nearer to the assault beaches than Rouen was visited. A bombing programme was directed against the principal road and rail bridges over the rivers Seine, Oise, Meuse and the Albert Canal. This accorded with real invasion requirements, but again drew attention to the Pas de Calais by severing the communications which appeared to lead in that direction. When attacking coast defences and enemy radar installations a proportion of two in the cover to one in the assault area was maintained.
Dummy landing craft at anchor in the River Orwell
Dummy landing craft at anchor in Dover Harbour
Allied bombing attacks on Northern France, the Netherlands and Northern Germany during the periods 29th May to 3rd June, and 4th to 6th June, 1944
The significance which the enemy might attach to the location of short-range fighter aircraft bases in England had always been recognised. The British Second Tactical Air Force and the American IX Tactical Air Command which were to support the invasion were now located in Hampshire and in Kent; but the concentrations in the New Forest and at Tangmere in the former county were considerably greater than those at Lympne, Hawkinge and Manston. It is true that the distance from Southampton to the Pas de Calais was no greater than that to Normandy, yet it was felt that a preponderance of fighter aircraft in Hampshire might provide the enemy with a useful clue. It was impossible to conceal these concentrations because the aircraft were already operational. To counteract this unfavourable circumstance, a large-scale operation against the Pas de Calais was carried out by the Second TAF on 29th May, in which sixty-six squadrons took part. These squadrons were given advanced and rear bases, the former being in Kent, Surrey and Sussex, the latter their normal ones in Hampshire. They operated from the advanced bases and landed at the rear ones to refuel and re-arm. The purpose was to indicate to the enemy our intention of using fighter aircraft located in the Southampton area against targets in North-Western France, which would in the normal course of events have been too far from their bases, but which could be reached by the employment of an intermediate airfield. The exercise was observed by GARBO’s sub-agent 7 (2), BRUTUS and TATE.4
The physical measures so far recorded were all designed to give an Eastern bias to the invasion preparations and to establish the false army group in South-Eastern England for future use. Other plans had been laid with the sole object of lowering German vigilance during the last critical days. The periods of wireless silence and of intense wireless activity which had been instituted at the end of 1943 were intended to prevent the enemy from discovering the date of the invasion through his reading of the wireless traffic. On reflection, however, it was felt that these measures, far from confusing the enemy, might be of direct assistance to him, since a period of wireless silence would denote a period of danger. If the networks to which the enemy had become accustomed could be simulated by artificial means at a time when the real formations were embarking under a wireless silence, the chances of putting the Germans off their guard would be greatly increased. During the month of May operators were accordingly infiltrated into the networks of all three Services in such a way that it was possible to simulate amphibious exercises in which the real assault divisions would appear to be engaged when they were, in fact, about to leave for France.5 Although such exercises were prepared for Force ‘S’ with the 3rd British Division and Force ‘J’ with the 3rd Canadian Division and were designed to begin on the day preceding the invasion, it was felt when the time came, in view of the fact that there had been no recent enemy reconnaissance, that such exercises might encourage German air observation at the very moment when it was least wanted. The exercises were therefore cancelled. Instead, while the troops were on their way across the Channel ‘the most “humdrum” of HF exercises between the more important ships were simulated and certain ship to shore waves were taken over by mobile stations ashore impersonating ships’.
A novel device for distracting the enemy’s attention from affairs in this country on the eve of the invasion was provided by Plan COPPERHEAD. It was known that the Spaniards had an observation post overlooking the airfield at Gibraltar. This post was manned by a non-commissioned officer and ten men, and observation was continuous. Reports of all arrivals and departures were made immediately to the Spanish authorities, and these found their way ultimately to Berlin. At the beginning of April an actor called Clifton James, then serving in the Royal Pay Corps, was found who bore a close personal resemblance to Field-Marshal Montgomery. He was dressed in the Field-Marshal’s clothes and, having accompanied him in the guise of a newspaper reporter for some weeks in order that he could study his characteristics, he set off on 27th May in a York aeroplane accompanied by a sham brigadier and ADC for North Africa. The ostensible purpose of the visit was a meeting with General Wilson and General Patch to co-ordinate, with the French High Command, the operations against Southern France which were to precede the launching of OVERLORD.
Lieutenant Clifton James who visited Gibraltar on 27th May, 1944 disguised as Field Marshal Montgomery
It was arranged that the Field-Marshal and his party should break their journey for a few hours at Gibraltar and call on the Governor. Steps were taken to ensure that other Spaniards who would be likely to relate their experiences on the other side of the frontier should meet him. On arrival in North Africa Lieutenant James and his party dropped their disguise and after a few days in Cairo returned unostentatiously to London. COPPERHEAD was supported by the Mediterranean-controlled agents but not by those in the United Kingdom.
