Key facts of the case:
Z appealed against a decision of the Special Immigration Appeal Commission (SIAC) upholding the Secretary of State's refusal to admit him to the United Kingdom. Z, an EU citizen, had been refused admission to the UK pursuant to the Immigration (European Economic Area) Regulations 2006 reg.19. Although his exclusion restricted his rights of free movement and residence, the SIAC held that it was justified on imperative grounds of public security. Its decision was based principally on closed material which had not been disclosed to Z or his representatives. Not even the gist of the case against Z had been disclosed. The Court of Appeal dismissed Z's domestic law grounds of appeal. However, there remained the question of whether he had been given sufficient disclosure of the case against him to comply with the requirements of EU law. Directive 2004/38 art.30(2) required that an individual in Z's position should be informed "precisely and in full" of the grounds on which a decision taken under art.27 had been based, unless that was contrary to the interests of national security. The Court of Appeal referred to the Court of Justice of the European Union the question of whether art.30(2) meant that an individual in Z's position had to be informed of the essence of the grounds for the exclusion decision, even if the domestic court considered that such disclosure would be contrary to the interests of national security (ZZ v Secretary of State for the Home Department  EWCA Civ 440).
8. Article 47 of the Charter of Fundamental Rights of the European Union ("the Charter") is relevant to the interpretation of those provisions of the Directive. It provides: "Everyone whose rights and freedoms guaranteed by the law of the Union are violated has the right to an effective remedy before a tribunal in compliance with the conditions laid down in this Article …. It should also be noted that Article 52(1) of the Charter, to which the CJEU makes specific reference. It provides that any limitation on the exercise of the rights and freedoms recognised by the Charter must be provided for by law "and respect the essence of those rights and freedoms"; and that subject to the principle of proportionality, limitations may be made only if they are necessary and genuinely meet objectives of general interest recognised by the Union or the need to protect the rights and freedoms of others. [Para. 4] The rival contentions of the parties on the relevant aspect of the appeal against SIAC's decision were conveniently summarised at para 13 of the judgment of Maurice Kay LJ when the matter was first before this court. The appellant contended that he was entitled to an "effective remedy" pursuant to Article 47 of the Charter. This extended to an entitlement to disclosure of at least the gist of the closed material which was pivotal to the case against him in SIAC because, without such disclosure, his remedy in SIAC was simply not effective. He relied on domestic, Strasbourg and Luxembourg authority to support this approach to an effective remedy. On the other hand, the case for the Secretary of State was that Article 4(2) of the Treaty on European Union ("national security remains the sole responsibility of each Member State") and Article 346(1)(a) of the TFEU ("no Member State shall be obliged to supply information the disclosure of which it considers contrary to the essential interests of its security"), read in conjunction with Article 6 of the Treaty on European Union ("the provisions of the Charter shall not extend in any way the competences of the Union as defined in the Treaties") and the corresponding provision in Article 51(2) of the Charter, had the effect that the appellant could not draw on Article 47 of the Charter to establish a right to disclosure of information which SIAC had found to be contrary to the interests of national security: the issue was one expressly reserved to Member States and was beyond the competence of the EU.