Western Union Defence Organisation

From April 1948, the member states of the Western Union (WU), decided to create a military agency under the name of the Western Union Defence Organisation (WUDO). WUDO was formally established on September 27–28, 1948.

The objective of WUDO was to provide for the coordination of defence between the five powers in the military and supply fields and for the study of the tactical problems of the defence of Western Europe; in addition, to provide a framework on which, in the event of any emergency, a command organization could be built up.

The Treaty of Brussels contained a mutual defence clause as set forth in Article IV:

Article V set forth the obligations of Brussels Pact members to cooperate with the United Nations Security Council to maintain international peace and security, and Article VI set forth the obligations of Brussels Pact members to not enter any third-party treaties that conflicted with the Treaty of Brussels.

The overall command structure was patterned after the wartime Supreme Headquarters Allied Expeditionary Force, which included a joint planning staff.

WUDO's organisational chart as of November 1948, in which solid and dashed lines indicate control and liaison lines, respectively:

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Direction and control was provided by the Western Union Defence Committee which, in peacetime, was composed of the national defence ministers. The Defence Committee was served by the Chiefs-of-Staff Committee and the Military Supply Board, meeting regularly in London. These bodies were analogous to the U.K.'s Chiefs of Staff Committee and Joint War Production Staff, respectively.