4.  The applicants are serving either life sentences or whole-life sentences in different prisons in Bulgaria. 5.  The applicant is currently serving a whole-life imprisonment sentence in Belene Prison. The sentence was delivered by the Dobrich Regional Court in 2003. It was confirmed on appeal in February 2004 and, subsequently, by the Supreme Court of Cassation in a final judgment of 19 October 2004. 6.  As it is apparent from documents in the file, the applicant had unsuccessfully sought presidential clemency several times since 2007. He was initially placed in the high-security wing of Varna Prison where he started serving his sentence; since 2004 he has been under the “special regime”. 7.  He described, and the Government did not comment on, the conditions under which he had been detained there as follows. His cell measured 5.5 by 3 metres and had a small grilled window which did not let much light in during the day. The lighting at night was also insufficient. The cell was humid, badly heated during the winter and deprived of ventilation during the summer. Given that in the cell there was neither running water, nor toilet facilities, the applicant had had to use a bucket to relieve himself. He was allowed to leave his cell three times a day, during meal times, for about forty-five minutes each time, in order to slop out, eat, wash himself and re-fill his water bottle from the tap. The prison was infested with cockroaches and rats, and he was only allowed to shower once a fortnight. The food was insufficient in quantity and of poor quality. During visits, he was separated from his family and lawyers by a grill and the meetings always took place in the presence of prison staff. His correspondence was routinely read by prison staff as he was obliged to transmit his letters to the outside world in open envelopes. The envelopes carrying correspondence with his lawyer bore a stamp showing that they had been checked. 8.  Both parties submitted that the applicant had been transferred to Belene Prison on 17 February 2009, where he continued to serve his sentence under the “special regime”. He was detained in the high-security wing of this prison, alone in a cell. 9.  According to the Government, since the beginning of his time in that prison, the applicant had gone on several hunger strikes. According to documents in the file, at the beginning of his stay in Belene Prison he demonstrated suicidal intentions and was identified as aggressive and hostile, as well as prone to attempting to escape. On the basis of an order of the prison governor of 19 February 2009, he did not take part in collective activities with other inmates, even those in his own category. In addition, the Government submitted that owing to lack of physical space in the prison, it was impossible to organise collective sport activities, or gather inmates for the purposes of reading, listening to music, playing board games or using the computer. Also, they emphasised that the impossibility was underpinned by the personal characteristics of the inmates which made them incompatible with each other and were an impediment to the authorities’ organising joint activities for them. 10.  The parties submitted that the applicant’s cell in Belene Prison was secured by a door and an external grill, both of which were locked. The light bulb remained on throughout the night, for security purposes, which the applicant claimed interfered with his sleep. His daily walks in the open air took place in a grilled space measuring, according to the applicant and not disputed by the Government, about 15 sq. m, where only persons serving life sentences were taken. According to the applicant, its floor was partially made of bare cement and there was no sports equipment there. According to the Government, there was a climbing wall, a bench and a fixed-height bar. Both parties submitted that each time the applicant left the high-security wing of the prison, he was handcuffed and the handcuffs were shackled to a belt. He claimed that his correspondence was routinely checked. According to the Government, prisoners’ correspondence was checked out of security considerations. However, the authorities only checked the contents of the envelopes which the applicant received and not the text of the letters in them. 11.  In a final judgment of 15 May 2005 the Supreme Court of Cassation sentenced the applicant to life imprisonment. The documents in the case file indicate that he had been initially imprisoned in Lovech Prison and was transferred to Belene Prison on 6 October 2009 where he was placed in the high-security wing. 12.  The Government submitted that he had been serving his sentence under the “special regime” since 5 May 2005. 13.  The applicant submitted that he had been kept in isolation in Belene Prison under the “special regime” and that the living conditions in his prison cell were inadequate. In particular he claimed that he spent about twenty-three hours a day locked up in a very small, poorly lit cell with a non-secluded toilet close to his bed. 14.  The Government did not dispute his claims. They specified that the size of his cell was 6 sq. m, that it was a “normal” as opposed to a “punishment” cell, that he had a bed, a drawer, a sink and a toilet in his cell, and that there was enough space for him to move about in it. 15.  The applicant was sentenced to life imprisonment in a final judgment of 10 December 2001 of the Supreme Court of Cassation. 16.  The applicant complained that, in accordance with the “special regime” under which he had been serving his sentence, he had been permanently locked up in a cell which he had only been allowed to leave for no more than one and a half hours a day. He also alleged very poor living conditions, the presence of rats, insufficient lighting, tainted water, limited space and time for outdoor activities, and consistent overuse of handcuffs. 17.  The Government submitted that the applicant had been serving his sentence under the “special regime” in Bobov Dol Prison between 5 February 2002 and 19 April 2007 when his regime had been changed to “severe”. He had spent the following two years under the “severe regime” and on 1 June 2009 his regime had been changed to “strict”. During his stay in Bobol Dol Prison between 2002 and 2012 the applicant had been in the high-security wing, alone in a cell measuring just under 13 sq. m. The cell had contained a sink and a toilet separated from the rest of the space. Hygiene in the cell had been satisfactory; the bed sheets had been washed weekly and the prisoners had been provided with sanitary products once a month. The cells had been disinfected and treated against mice with the same frequency. 18.  The Government submitted that the applicant had been kept in a permanently locked up cell in Bobov Dol Prison, in strict compliance with the relevant legal provisions and in particular section 71(2) of the Execution of Punishments and Pre-trial Detention Act. As of February 2016, they specified that the applicant had formally satisfied the conditions for being detained together with other prisoners but that the applicant had considered himself not ready for it. 19.  On 24 July 2012 the applicant was transferred to Pazardzhik Prison upon his request and was placed in the high-security wing, in a cell measuring 7 sq. m. He expressed an interest in working but the authorities were not in a position to provide him with work. He had not committed disciplinary breaches to the time of application. As to the conditions of detention in Pazardzhik Prison, the Government submitted that he had not raised related grievances with the authorities. 20.  The applicant was sentenced for a number of offences and was given a total sentence of whole-life imprisonment in 2000. He complained that his sentence had amounted, from the time of its imposition, to inhuman and degrading punishment, in breach of Article 3 of the Convention and that he did not have an effective remedy in this connection. 21.  In a final judgment of 15 March 2010 the applicant was sentenced by an Austrian court to life imprisonment. He was transferred from Austria to Bulgaria on 15 July 2010 in order to serve his sentence. On 8 November 2010 the Vratsa Regional Court confirmed the sentence and accepted it for enforcement. This was upheld on appeal by the Sofia Appellate Court in a final decision of 9 February 2011. The applicant has been serving his sentence under the “special regime” since 18 February 2011. He is kept in a permanently locked cell in Vratsa Prison, in the high-security wing, in accordance with applicable rules for life prisoners under the Execution of Punishments and Pre-trial Detention Act. 22.  The applicant was sentenced to whole-life imprisonment on 28 February 2011 in a final judgment of the Supreme Court of Cassation. 23.  The applicant complained that his sentence had amounted, from the time of its imposition, to inhuman and degrading punishment, in breach of Article 3 of the Convention and that he did not have an effective remedy in this connection. 24.  The applicant was sentenced to life imprisonment in a final judgment of the Supreme Court of Cassation of 13 November 2008. He has been serving his sentence under the “special regime” in Varna Prison. He alleged that he spent his time almost permanently locked up in isolation from the other inmates, while the Government claimed that he was in “almost permanent contact with other inmates” without submitting more details. The applicant submitted that he had had to relieve himself in a bucket in his cell where there had been no running water. The Government clarified that this changed in 2012 when a toilet had been built in his cell. The food, according to the applicant and disputed by the authorities, was insufficient and of poor quality. 25.  The applicant was sentenced for different offences and given a total sentence of life imprisonment in a final judgment of 17 November 2011 by the Supreme Court of Cassation. The applicant has been serving his sentence in Stara Zagora Prison under the “special regime” in a permanently locked cell located in the high-security wing of the prison. The Government submitted that he was allowed to leave his cell twice a day for an hour at a time when he could see and communicate with other inmates detained in the same prison wing. He was also allowed to use sanitary facilities outside of his cell five times a day, and to shower twice a week. There was no toilet in the applicant’s cell and no ventilation system had been installed. 26.  The applicant had been serving a sentence of whole-life imprisonment in Pleven Prison since 1999 under the “special regime”. In 2003 he was placed under the lighter “severe regime” and a year later under the even lighter “strict regime” when he was also placed in a cell together with other inmates. 27.  He complained that his sentence had amounted, from the time of its imposition, to inhuman and degrading punishment, in breach of Article 3 of the Convention and that he did not have an effective remedy in this connection. 28.  The applicant was sentenced to life imprisonment and has been serving his sentence under the “special regime” since 2009. Until 2009 he was detained in Varna Prison and since 18 February 2009 he has been detained in Plovdiv Prison. He complained in respect of his detention after February 2009, the conditions of his detention before 18 February 2009 having been examined by the Court in an earlier case with application no. 16391/05, which was decided in a judgment of 10 January 2012. 29.  Both the applicant and the Government submitted that he was detained in a permanently locked cell and isolated from the other prisoners. The Government pointed out that the applicant left his cell for an hour in the morning and for an hour in the afternoon every day for exercise and to spend time in the open air. 30.  The applicant also claimed that the material conditions in which he had been serving his sentence were inadequate and that he had been offered no collective activities or other forms of occupation. 31.  The Government stated that he was enrolled in the following weekly activities: a catechism course lasting an hour-and-a-half per week; and a course in basic computer skills with hour-long sessions; he also had an additional hour in the open air, as well as half an hour to take a bath on Wednesday evenings. Furthermore, when various competitions had taken place in the prison, or there had been concerts or recitals, inmates serving life sentences had been offered a chance to attend them as spectators. The Government further clarified that the applicant’s regime had been changed to “strict” in 2015 but he had continued to be in the high-security wing; according to the Government, he had repeatedly stated that he had not wished to be placed together with other prisoners.