d notice

n. (British) D-Notice, official notice that the government sends to newspapers or other publications asking them to hold back and not publish sensitive information in order to protect the country

In Britain, a DA-Notice (called a D-Notice until 1993) is an official request to news editors not to publish items on specified subjects, for reasons of national security. The original D-Notice system was introduced in 1912, run as a voluntary system by a joint committee headed by an Assistant Secretary of the War Office and a representative of the Press Association. In 1971 all existing D-Notices were cancelled and replaced by standing D-Notices that gave general guidance on what could be published and what could not, and what would require further advice from the secretary of the Defence, Press and Broadcasting Advisory Committee (DPBAC). In 1993 the notices were renamed DA-Notices.
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