45. As a preliminary point, it should be recalled that, whilst, as Article 6(3) TEU confirms, fundamental rights recognised by the ECHR constitute general principles of EU law and whilst Article 52(3) of the Charter provides that the rights contained in the Charter which correspond to rights guaranteed by the ECHR are to have the same meaning and scope as those laid down by the ECHR, the latter does not constitute, as long as the European Union has not acceded to it, a legal instrument which has been formally incorporated into EU law (judgments in Åkerberg Fransson, C‑617/10, EU:C:2013:105, paragraph 44, and Inuit Tapiriit Kanatami and Others v Commission, C‑398/13 P, EU:C:2015:535, paragraph 45).

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47. In that regard, the explanations relating to Article 6 of the Charter, which, in accordance with the third subparagraph of Article 6(1) TEU and Article 52(7) of the Charter, have to be taken into consideration for the purpose of interpreting it (see, to that effect, judgments in Åkerberg Fransson, C‑617/10, EU:C:2013:105, paragraph 20, and Spasic, C‑129/14 PPU, EU:C:2014:586, paragraph 54), make clear that the rights laid down in Article 6 of the Charter correspond to those guaranteed by Article 5 of the ECHR and that the limitations which may legitimately be imposed on the exercise of the rights laid down in Article 6 of the Charter may not exceed those permitted by the ECHR, in the wording of Article 5 thereof. However, the explanations relating to Article 52 of the Charter indicate that paragraph 3 of that article is intended to ensure the necessary consistency between the Charter and the ECHR, ‘without thereby adversely affecting the autonomy of Union law and ... that of the Court of Justice of the European Union’.
48. Furthermore, in accordance with a general principle of interpretation, an EU measure must be interpreted, as far as possible, in such a way as not to affect its validity and in conformity with primary law as a whole and, in particular, with the provisions of the Charter (judgments in McDonagh, C‑12/11, EU:C:2013:43, paragraph 44, and Review of Commission v Strack, C‑579/12 RX-II, EU:C:2013:570, paragraph 40).
49. In permitting an applicant to be detained when the protection of national security or public order (‘ordre public’) so requires, point (e) of the first subparagraph of Article 8(3) of Directive 2013/33 provides for a limitation on the exercise of the right to liberty entrenched in Article 6 of the Charter.
50. Under Article 52(1) of the Charter, 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. In observance of the principle of proportionality, limitations may be imposed on the exercise of those rights and freedoms only if they are necessary and genuinely meet objectives of general interest recognised by the European Union or the need to protect the rights and freedoms of others.
51. It should be stated in this regard that since the limitation in question derives from a directive, which is a legislative act of the European Union, that limitation is provided for by law.
52. In addition, point (e) of the first subparagraph of Article 8(3) of Directive 2013/33 does not affect the essence of the right to liberty laid down in Article 6 of the Charter. That provision of the directive does not render the guarantee of that right less secure and — as is apparent from the wording of the provision and recital 15 of the directive — the power that it confers on Member States enables them to detain an applicant only on the basis of his individual conduct and under the exceptional circumstances referred to in the same provision, those circumstances also being circumscribed by all the conditions set out in Articles 8 and 9 of the directive.
53. Given that the objective pursued by point (e) of the first subparagraph of Article 8(3) of Directive 2013/33 is the protection of national security and public order, it must be held that a measure ordering detention which is based on that provision genuinely meets an objective of general interest recognised by the European Union. Moreover, the protection of national security and public order also contributes to the protection of the rights and freedoms of others. Article 6 of the Charter states in this regard that everyone has the right not only to liberty but also to security of person (see, to that effect, judgment in Digital Rights Ireland and Others, C‑293/12 and C‑594/12, EU:C:2014:238, paragraph 42).

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56. As to whether the power which that provision confers on Member States to detain an applicant on grounds related to the protection of national security or public order is necessary, the Court stresses that, in view of the importance of the right to liberty enshrined in Article 6 of the Charter and the gravity of the interference with that right which detention represents, limitations on the exercise of the right must apply only in so far as is strictly necessary (see, by analogy, with regard to the right to respect for private life, judgment in Digital Rights Ireland and Others, C‑293/12 and C‑594/12, EU:C:2014:238, paragraph 52).

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81. It should also be noted that, according to the case-law of the European Court of Human Rights relating to Article 5(1) of the ECHR, if the execution of a measure depriving a person of liberty is to be in keeping with the objective of protecting the individual from arbitrariness, that means, in particular, that there can be no element of bad faith or deception on the part of the authorities, that execution of the measure is consistent with the purpose of the restrictions permitted by the relevant sub-paragraph of Article 5(1) ECHR and that the deprivation of liberty concerned is proportionate in relation to the ground relied on (see, to that effect, judgment of the European Court of Human Rights in Saadi v. the United Kingdom, no. 13229/03, § 68 to 74, ECHR 2008). As is apparent from the reasoning set out in connection with the examination of its validity in the light of Article 52(1) of the Charter, point (e) of the first subparagraph of Article 8(3) of Directive 2013/33 — whose scope, in view of the context of the provision, is strictly circumscribed — satisfies those requirements.
82. The answer to the question referred for a preliminary ruling is therefore that consideration of point (e) of the first subparagraph of Article 8(3) of Directive 2013/33 has disclosed no factor of such a kind as to affect the validity of that provision in the light of Articles 6 and 52(1) and (3) of the Charter.