A. AND OTHERS v. THE UNITED KINGDOM JUDGMENT 41 SIAC was required to carry out a first review to ensure that the certificate was still justified six months after the issue of the certificate or six months after the final determination of an appeal against certification, and thereafter at three-monthly intervals. Under section 30 of the 2001 Act, any legal challenge to the derogation under Article 15 of the Convention had also to be made to SIAC. 92. SIAC has a special procedure which enables it to consider not only material which can be made public (“open material”) but also material which, for reasons of national security, cannot (“closed material”). Neither the appellant nor his legal adviser can see the closed material. Accordingly, one or more security-cleared counsel, referred to as “special advocates”, are appointed by the solicitor-general to act on behalf of each appellant. 93. In the certification appeals before SIAC at issue in the present case, the open statements and evidence concerning each appellant were served first, and the special advocate could discuss this material with the appellant and his legal advisers and take instructions generally. Then the closed material would be disclosed to the judges and to the special advocate, from which point there could be no further contact between the latter and the appellant and/or his representatives, save with the permission of SIAC. It was the special advocate’s role during the closed sessions to make submissions on behalf of the appellant, both as regards procedural matters, such as the need for further disclosure, and as to the substance of the case. In respect of each appeal against certification, SIAC issued both an “open” and a “closed” judgment. The special advocate could see both but the detainee and his representatives could see only the open judgment. E. Declarations of incompatibility under the Human Rights Act 1998 94. Section 4 of the 1998 Act provides that where a court finds that primary legislation is in breach of the Convention, the court may make a declaration of incompatibility. Such a declaration does not affect the validity of the provision in respect of which it is made and is not binding on the parties to the proceedings in which it is made, but special arrangements may be made (section 10) to amend the provision in order to remove the incompatibility (see, further, Burden v. the United Kingdom [GC], no. 13378/05, §§ 21-24 and 40-44, ECHR 2008). F. The Terrorism Act 2006 95. The Terrorism Act 2006 came into force on 30 March 2006, creating a number of offences to extend criminal liability to acts preparatory to the terrorist offences created by the Terrorism Act 2000. The new offences were encouragement, dissemination of publications, preparation and training. The offences were designed to intervene at an early stage in terrorist activity and