(b) To train persons to carry out all forms of clandestine activity, e.g. covert propaganda, rumours, influencing public persons and minorities; and to study objectives for sabotage. (c) To study, to devise and to maintain small reserves of all material required for sabotage and clandestine operational activities of all types, including communications. (d) In such cases as the appropriate department or the Chiefs of Staff may think fit, and subject to the express approval of the Foreign Office, to serve the clandestine operational requirements of His Majesty's Government abroad by giving covert support to British national interests where threatened, e.g.