Memorandum C.C.S. 166/1/D by the Combined Chiefs of Staff, 21 January 1943:
C.C.S. 166/1/D was a revised and expanded version of the "C.C.S 166" document which had been presented for discussion to the Combined Chiefs of Staff on 20 January by the British Chiefs of Staff. The discussions brought up several issues, such as how to phrase the memorandum to balance the concerns of the different stake-holders about the priority to give to anti-U-boat activities as opposed to support for the planned operations to take place in the Mediterranean theatre. Two changes were proposed and agreed that the addition "for political reasons" should be inserted into "... issued from time to time by His Majesty's Government..." and that the word "synthetic" was removed "Synthetic oil plants". Further changes were made to the British draft of the memorandum in the ordering of some of the sentences. A modified version of the Casablanca directive as sent to RAF Bomber Command on 4 February 1943:
Arthur "Bomber" Harris, the commander of RAF Bomber Command from 1942, included the directive in his papers with an attached note to the bottom.
The RAF Bomber command version contains most of the information that is in the C.C.S. memorandum but in a different order and in the note at the bottom it makes it clear that this directive replaced general directive No. 5, that is often referred to as the Area Bombing Directive. Missing from the Bomber command directive are mention of "point 4" in the C.C.S. version – objectives of great but fleeting importance such as the German Fleet – and point 7 which was redundant as RAF Bomber Command already obeyed orders originating from the Chiefs of Staff Committee whatever their military or political origins. Despite the lack of an explicit mention of "point 4" in the Bomber Command version of the directive, Bomber Command was involved in attacking the German capital ships only a few days after this directive reached them, when along with the Royal Navy and its Fleet Air Arm they failed to prevent the successful "Channel Dash" made by the,,, supported by a number of smaller ships, from France to their home ports. In his post war book Bomber offensive Harris mentions the Casablanca directive at the start of chapter seven "The offensive underway". In it he emphasises the "Object" paragraph of the directive issued to the RAF and mentions the "Primary" paragraph in passing. He explains that the subject of morale had been dropped and that he was to proceed with the "general 'disorganisation' of German industry" but that some parts of that industry, such as U-boat building, had a higher priority than others, from which he drew the conclusion that it "allowed to attack any German industrial city of 100,000 inhabitants and above" and that the Ruhr remained the principal target for the RAF.
