74 A. AND OTHERS v. THE UNITED KINGDOM JUDGMENT domestic level. As the House of Lords held, the question of proportionality is ultimately a judicial decision, particularly in a case such as the present where the applicants were deprived of their fundamental right to liberty over a long period of time. In any event, having regard to the careful way in which the House of Lords approached the issues, it cannot be said that inadequate weight was given to the views of the executive or of Parliament. 185. The Government also submitted that the House of Lords erred in examining the legislation in the abstract rather than considering the applicants’ concrete cases. However, in the Court’s view, the approach under Article 15 is necessarily focused on the general situation pertaining in the country concerned, in the sense that the court – whether national or international – is required to examine the measures that have been adopted in derogation of the Convention rights in question and to weigh them against the nature of the threat to the nation posed by the emergency. Where, as here, the measures are found to be disproportionate to that threat and to be discriminatory in their effect, there is no need to go further and examine their application in the concrete case of each applicant. 186. The Government’s third ground of challenge to the House of Lords’ decision was directed principally at the approach taken towards the comparison between non-national and national suspected terrorists. The Court, however, considers that the House of Lords was correct in holding that the impugned powers were not to be seen as immigration measures, where a distinction between nationals and non-nationals would be legitimate, but instead as concerned with national security. Part 4 of the 2001 Act was designed to avert a real and imminent threat of terrorist attack which, on the evidence, was posed by both nationals and non-nationals. The choice by the Government and Parliament of an immigration measure to address what was essentially a security issue had the result of failing adequately to address the problem, while imposing a disproportionate and discriminatory burden of indefinite detention on one group of suspected terrorists. As the House of Lords found, there was no significant difference in the potential adverse impact of detention without charge on a national or on a non-national who in practice could not leave the country because of fear of torture abroad. 187. Finally, the Government advanced two arguments which the applicants claimed had not been relied on before the national courts. Certainly, there does not appear to be any reference to them in the national courts’ judgments or in the open material which has been put before the Court. In these circumstances, even assuming that the principle of subsidiarity does not prevent the Court from examining new grounds, it would require persuasive evidence in support of them. 188. The first of the allegedly new arguments was that it was legitimate for the State, in confining the measures to non-nationals, to take into account the sensitivities of the British Muslim population in order to reduce