64 A. AND OTHERS v. THE UNITED KINGDOM JUDGMENT 151. Finally, the House of Lords’ conclusion had turned not on a rejection of the necessity to detain the applicants but instead on the absence of a legislative power to detain also a national who posed a risk to national security and was suspected of being an international terrorist. However, there were good reasons for detaining only non-nationals and the Convention expressly and impliedly recognised that distinction was permissible between nationals and non-nationals in the field of immigration. The primary measure which the Government wished to take against the applicants was deportation, a measure permitted against a non-national but not a national. The analogy drawn by the House of Lords between “foreigners [such as the applicants] who cannot be deported” and “British nationals who cannot be deported” was false, because the applicants at the time of their detention were not irremovable in the same way that a British citizen is irremovable. Furthermore, at the relevant time the Government’s assessment was that the greater risk emanated from non-nationals and it was legitimate for a State, when dealing with a national emergency, to proceed on a step-by-step basis and aim to neutralise what was perceived as the greatest threat first, thereby also freeing resources to deal with the lesser threat coming from British citizens. In addition, it was reasonable for the State to take into account the sensitivities of its Muslim population in order to reduce the chances of recruitment among them by extremists. 3. The third party, Liberty 152. Liberty (see paragraph 6 above) submitted that, by reserving before the domestic courts the issue whether the detention was compatible with Article 5 § 1, the Government had deprived the Court of the benefit of the views of the House of Lords and had pursued a course of action which would not be open to an applicant. In any event, the detention did not fall within the exception in Article 5 § 1 (f), since Part 4 of the 2001 Act permitted indefinite detention and since there was no tangible expectation of being able to deport the applicants during the relevant time. If the Government were unable to remove the applicants because of their Article 3 rights, they could not properly rely on national security concerns as a basis for diluting or modifying their Article 5 rights. Instead, the proper course was either to derogate from Article 5 to the extent strictly required by the situation or to prosecute the individuals concerned with one of the plethora of criminal terrorist offences on the United Kingdom’s statute books, which included professed membership of a proscribed organisation, failure to notify the authorities of suspected terrorist activity, possession of incriminating articles and indirect encouragement to commit, prepare or instigate acts of terrorism (see paragraphs 89 and 95 above).