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 [for political reasons] 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.