The closed material procedure (CMP) is an incredibly controversial mechanism raising obvious implications for the fair trial rights of those subject to it. It was therefore noteworthy that in 2009, when assessing the Convention-compliance of the procedure, the Grand Chamber of the European Court of Human Rights delivered its much-celebrated judgment of A and Others v. United Kingdom, holding that even the very serious threat posed by international terrorism could not justify the total erasure of the fundamental right to a fair trial. Since then, the UK courts have grappled with the terms of the judgment, developing a jurisprudence which respects, to some extent, the findings of A, but subjects it to increasing number of exceptions and qualifications. The European Court has finally had an opportunity to evaluate the UK’s approach in its decision in Tariq v. United Kingdom. This piece will outline the operation of the CMP, before detailing the European Court’s approach in A, how this has been interpreted by domestic courts and how the European Court has now responded. Some comments will be offered regarding what this final development now means for the future of the CMP.