The Western Union (WU) was a military alliance established between France, the United Kingdom and the three Benelux countries (Belgium, The Netherlands and Luxemburg) between 1948 and 1954.

This badge is universally worn by the joint staff of the five Western Union Powers of the Brussels Treaty (Britain, France, Belgium, Holland and Luxembourg).

The badge, in which the five gold links forming a pentagon on a blue background symbolize the five Western Powers, is worn on did sleeve below the shoulder tide in the same position as all British Formation.

A photo of the flag is shown in the book entitled Badges on Battledress by Howard N. Cole (Aldershot, Gale & Polden, 1953).

The flag ceased to be used upon the creation of NATO's Headquarters, Allied Land Forces Central Europe (AFCENT) in August 1953, at which point one extra link was added to the emblem, symbolising the United States.