A certificate signed by a Minister of the Crown certifying that disclosure of information to the public would, or would be likely to, adversely affect national security is conclusive evidence of that fact.

A certificate under paragraph (1) may identify the information to which it applies by means of a general description and may be expressed to have prospective effect.

A document purporting to be a certificate under paragraph (1) shall be received in evidence and deemed to be such a certificate unless the contrary is proved.

A document which purports to be certified by or on behalf of a Minister of the Crown as a true copy of a certificate issued by that Minister under paragraph (1) shall in any legal proceedings be evidence (or in Scotland, sufficient evidence) of that certificate.

The power conferred by paragraph (1) on a Minister of the Crown shall not be exercisable except by a Minister who is a member of the Cabinet or by the Attorney General, the Advocate General for Scotland or the Attorney General for Northern Ireland.