For ten days prior to D Day the Battalion, with Lt-Colonel I. C. Harris in command, and with Major B. J. FitzG Donlea, MC, as Second in Command, was "sealed" in a camp which allowed of no entry or exit. There the problem of briefing had to be considered and preparations made. The sorting of operational maps started immediately. As these were of course highly secret they had to be made up into craft loads for each individual, and sealed only to be opened when the craft sailed.
As an indication of the number of maps issued, each officer had fourteen, and each section leader seven maps. Each officer also had two folders of aerial photographs showing a wave-top view of the coast, the Assembly area, the immediate area of the beachhead, the anti-tank ditch, and the town of Caen.
The problem of briefing. which had to be carried out prior to embarkation was solved by the issue of Bogus maps. These were correct in every detail except that bogus names were substituted for the real names. Thus Caen was known as Poland and other places were concealed by such names as Japan, Mexico, Dublin, Belfast.
From an Intelligence point of view we had every possible aid to ensure a thorough briefing. It was carried out in special marquees which contained plentiful supplies of bogus maps, map enlargement scaled one foot to a mile, models, stereoscopic photos of the whole area and enlargement of all places of particular interest to us like Caen, the beaches, assembly and concentration areas and anti-tank ditches.
The Commanding Officers Orders and briefing of all officers including supporting arms took the whole of the first day. The briefing marquees were then allotted on a Company and Platoon basis, and briefing continued for three days under the supervision of the I.O. and the Intelligence Section. The principle had been laid down that, despite the risk from the point of view of security, the fullest possible information was to be passed on to the men who had to do the fighting. It can safely be said that no army had ever before had such a wealth of information made available to help it to fight.