4.  The facts of the case, as submitted by the parties, may be summarised as follows.
5.  The applicant was born in Baku, Azerbaijan, in 1992 and came to Russia in 2003, together with his mother and grandmother. He graduated from a secondary school and a vocational training college in St Petersburg. He has no identity documents.
6.  On 7 February 2014 the Kirovskiy District Court in St Petersburg found the applicant guilty of illegally residing in Russia, which was an offence Article 18.8 § 3 of the Code of Administrative Offences, imposed a fine on him and ordered his administrative removal from Russia. The judgment described him as a “native” (уроженец) and a national of Azerbaijan. Pending his removal, the applicant was to be detained in the special facility for the detention of aliens (СУВСИГ УФМС по СПб и ЛО) located in Krasnoye Selo in the Leningrad Region.
7.  On 12 February 2014 the Federal Migration Service requested the Consulate General of Azerbaijan in St Petersburg to submit information about the applicant’s nationality. Replying to that inquiry, on 14 April 2014 the Consulate confirmed that the applicant was not a national of that State.
8.  On 19 May 2014 a bailiff asked the District Court in St Petersburg to discontinue the enforcement proceedings because the applicant could not be issued with travel documents or removed from Russia.
9.  By a judgment of 17 July 2014, as upheld on appeal on 30 October 2014, the St Petersburg courts refused to discontinue the proceedings, finding that the bailiff had not shown that she had taken sufficient measures to secure the applicant’s removal.
10.  On 7 August 2014 counsel for the applicant asked the St Petersburg City Court to review the Kirovskiy District Court’s judgment by way of supervisory review, to annul the sanction of administrative removal and to release the applicant. Counsel pleaded in particular that the applicant’s removal was not a realistic prospect and that his continued detention could only be justified if deportation proceedings were genuinely in progress. On 25 November 2014 a deputy president of the City Court acceded to her request. Noting that the applicant was not an Azerbaijani national, the judge found that his removal was not feasible and that his detention was likely to become indefinite. He amended the judgment, replacing the removal with the requirement to leave Russia voluntarily under control.
11.  On 27 November 2014 the applicant was released.
12.  The applicant described his conditions of detention as follows. From 7 to 20 February 2014 he shared Cell 307 measuring 17 square metres with ten other detainees. It was not furnished, inmates unrolled mattresses for the night. From 20 February to 5 May 2014 he was held in a smaller, seven‑square-metre cell (Cell 310), together with five or six persons. Two-tier bunk beds were brought in only in late April 2014. From 5 May to 27 November 2014 he was in Cell 309 measuring seventeen square metres. Initially it had accommodated twelve persons but their number rose to seventeen in November when they started renovating the cells on the seventh and eighth floors of the facility. Detainees had to remain within the floor on which their cell was located; they could not go outside or to other floors. Outdoor exercise was limited to a fifteen-minute walk once a week because there was not enough staff to supervise the detainees. The facility did not have a library, board games, radio or workshop, or offer any other meaningful activities.