Operation Neptune, naval orders including air operations covering estimate of allied air forces avaliable in the UK on 1 June 1944, with types of Allied Aircraft taking part and Enemy Aircraft which may be sighted; general instruction for air defence covering orders for Air Warning and fighter direction, rules for Allied Air force, air defence of the beaches,ballons and smoke; instruction for the build up covering composition of escort groups, landing ships and crafts, code letters for ships' number boards and transfer of warships between Home Commands.

Administrative / biographical background
During WWII a level of clearance called "Bigot" was adopted by the allies. This was in order to create a smaller circle of individuals who were cleared to know information.