MEDVEDYEV AND OTHERS v. FRANCE JUDGMENT 25 no. 24952/94, § 44, ECHR 2002-X; Azinas, cited above, §§ 32 and 37; Sejdovic v. Italy [GC], no. 56581/00, § 41, ECHR 2006-II; and Mooren, cited above). Only exceptional circumstances, such as the fact that the grounds for the objection of inadmissibility came to light late in the day, can dispense a government from the obligation to raise their objection in their observations on the admissibility of the application before the adoption of the Chamber’s admissibility decision (see N.C. v. Italy, cited above, § 44; Sejdovic, cited above, § 41; and Mooren, cited above). 70. In the instant case, the Court notes that, in the written observations on admissibility which they submitted to the Chamber, the Government did not argue that the complaints were incompatible ratione materiae with the provisions of Article 5 of the Convention, and the Court can discern no exceptional circumstance capable of dispensing the Government from raising that objection in their observations to the Chamber on admissibility. 71. The Government are accordingly estopped from raising a preliminary objection of incompatibility ratione materiae at this stage in the proceedings. In spite of this estoppel, however, the Court must examine this question, which goes to its jurisdiction, the extent of which is determined by the Convention itself, in particular by Article 32, and not by the parties’ submissions in a particular case (see Demir and Baykara v. Turkey [GC], no. 34503/97, ECHR 2008). 72. First of all, referring also to its finding that the applicants were within the jurisdiction of France for the purposes of Article 1 of the Convention, the Court considers that the preliminary observations on the applicability of Article 5 actually concern the merits of the application. 73. As to the observations concerning the existence or otherwise of the deprivation of liberty, the Court reiterates that Article 5 – paragraph 1 of which proclaims the “right to liberty” – is concerned with a person’s physical liberty. Its aim is to ensure that no one should be dispossessed of this liberty in an arbitrary fashion. In order to determine whether someone has been “deprived of his liberty” within the meaning of Article 5 the starting-point must be his concrete situation and account must be taken of a whole range of criteria such as the type, duration, effects and manner of implementation of the measure in question (see Amuur v. France, 25 June 1996, § 42, Reports of Judgments and Decisions 1996-III). The difference between deprivation of and restriction upon liberty is merely one of degree or intensity, and not one of nature or substance (see Guzzardi v. Italy, 6 November 1980, Series A no. 39, and Amuur, cited above). 74. In the Court’s opinion, while it is true that the applicants’ movements prior to the boarding of the Winner were already confined to the physical boundaries of the ship, so that there was a de facto restriction on their freedom to come and go, it cannot be said, as the Government submitted, that the measures taken after the ship was boarded merely placed a restriction on their freedom of movement. The crew members were placed