2. The following authorities may all be concerned :The Admiralty The War Office The Air Ministry G.H.Q. Home Forces Coastal Command Bomber Command Fighter Command A.C.O. Colonel Stanley S.O.E. "C" The Security Service. 3. Operations planned by any of these authorities may conflict with operations planned by one or more of the others. It is therefore necessary to devise some system which, while conforming to the principle of restricting information about operations to the essential minimum number of people, ensures that operations do not clash.