There have been a number of articles recently in connection with some of the ways in which the UK Intelligence Services obtain information from foreign sources. Although none of these recent articles has contravened any of the guidelines contained within the Defence Advisory Notice System, the intelligence services are concerned that further developments of this same theme may begin to jeopardize both national security and possibly UK personnel.It particularly warned against reporting on:
specific covert operations, sources and methods of the security services, SIS and GCHQ, Defence Intelligence Units, Special Forces and those involved with them, the application of those methods, including the interception of communications and their targets; the same applies to those engaged on counter-terrorist operations.The D-notice system was first set up in 1912 and operates in accordance with a voluntary code — providing "advice and guidance to the media about defence and counter-terrorist information the publication of which would be damaging to national security." In 2010, for instance, a D notice was reportedly issued prior to WikiLeaks' release of thousands of US government diplomatic cables. A D notice has no formal legal authority, but defying it can make journalists vulnerable to prosecution under the UK's Official Secrets Act.