The United Kingdom Special Forces (UKSF) is a directorate comprising the Special Air Service, the Special Boat Service, the Special Reconnaissance Regiment, the Special Forces Support Group, 18 (UKSF) Signal Regiment and the Joint Special Forces Aviation Wing, as well as the supporting No. 47 Squadron. In British freedom of information law, "special forces" has been defined as "those units of the armed forces of the Crown and the maintenance of whose capabilities is the responsibility of the Director of Special Forces or which are for the time being subject to the operational command of that Director". The Royal Marine Commandos and the Ranger Regiment (United Kingdom) are special operations–capable forces, however they do not form part of the UKSF. The government and Ministry of Defence (MOD) have a policy of not commenting on the UKSF, in contrast to other countries including the United States, Canada and Australia. In 1996, the UKSF introduced a requirement that serving members sign a confidentiality contract preventing them from disclosing information for life, without the prior approval of the MOD, following the publication of several books written by ex-service members. From Wikipedia
