The Secret Registry series, comprising extracts from files, contains 'personal messages' - a type of communication used between Commonwealth leaders and routed through their High Commissioners - between the Federal Prime Minister and the Prime Minister of the United Kingdom and the various Secretaries of State (Colonies, Commonwealth Relations, and the First Secretary of State - Butler), as well as correspondence and telegrams/telexes between the Federal Prime Minister, the Federal High Commissioner in London, and the United Kingdom High Commissioner in Salisbury (Harare) and, less frequently, the governors of the northern territories and the Prime Minister of Southern Rhodesia (Zimbabwe). For similar material for territorial constitutions, see MSS. Welensky Papers 216/1-225/3. For further references, see MSS. Welensky Papers 154/2, 199/4-5, 211/1, 213/5-7, 220/4, 400/5-402/1, 407/3-4, and 408/2-3.