In the UK the original D-Notice system was introduced in 1912 and 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.

Any D-Notices or DA-notices are only advisory requests so are not legally enforceable and hence news editors can choose not to abide by them. However, they are generally complied with by the media.[1]

In 1971, all existing D-Notices were cancelled and replaced by standing D-Notices, which 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).

And editors before the sixties knew better than to disregard these "REQUESTS".