4.  The applicants are serving either life sentences or a lengthy period of imprisonment in different prisons in Bulgaria. 5.  The applicant was sentenced to twenty years imprisonment in November 2011. As it transpires from documents in the file, pursuant to an order of the prison governor referring to section 248(1)(1) of the 2009 Execution of Punishments and Pre-Trial Detention Act (see paragraph 18 below), on 29 July 2011 the applicant was placed in isolation in Burgas Prison, in a permanently locked cell without the possibility to take part in collective activities. The applicant described, and the Government did not comment on, the conditions under which he had been detained there as follows. He was kept in isolation since 29 July 2011, without running water and toilet in his cell. He had to use the same bucket to relieve himself and as a chair at meal times as he ate in the cell. The heating was insufficient in winter and the temperature was excessively high in the cell in summer. There was poor ventilation and poor natural light in his cell. Also, the light in his cell was kept on during the entire night, the cell was infested with rats and cockroaches, and the latter sometimes also reached his food. On an unspecified date before July 2016 the applicant was transferred to Varna Prison and he has not complained about the conditions there. 6.  The applicant was sentenced to life imprisonment in a final decision by the Supreme Court of Cassation of 10 November 2005. He complained about the conditions under which he has been serving his sentence since 12 July 2007 when he had been transferred to Plovdiv Prison. He described, and the Government did not comment on, the conditions under which he had been detained there as follows. There has been no running water or toilet in his cell which measured about 6 square metres. He has had to use a bucket to comply with the needs of nature in his cell; he has also been taking his food in the cell. The cell was overly humid, which was not mitigated by the fact that he has had to hang his clothes to dry there after washing them. The ventilation was poor, which aggravated the repugnant smell coming out of the sewers situated close to his cell. In the summer the temperatures were very high and in the winter the heating was switched off at around 6 p.m. as a result of which it became very cold in his cell. 7.  In addition, between 2007 and 2011 he had been kept under the very impoverished and restrictive “special regime”, alone in a cell. According to the applicant, while his regime was formally changed from “special” to the lighter “strict” one on 6 June 2011, in reality the restrictions and inadequate conditions in which he has been detained did not change. He has been handcuffed systematically upon leaving his cell. 8.  The applicant was sentenced to whole-life imprisonment on 26 July 2004 in a final judgment of the Supreme Court of Cassation. He complained about the “special regime” and inadequate material conditions of detention in which he has been serving his sentence since 24 January 2012 in Varna Prison. The period of detention of this applicant before that date was subject to examination in an earlier Court’s judgment in which it found a violation of Article 3 on account of the excessively strict prison regime and poor conditions of detention (see Iordan Petrov v. Bulgaria, no. 22926/04, § 128, 24 January 2012). 9.  The applicant submitted that he has been serving his sentence in isolation from the surrounding world, namely in a permanently locked cell. He has not been involved in any collective activities or provided with work and has been denied contact with prisoners who are serving sentences lighter than life imprisonment. Every time he was taken out of the high security zone, he has been hand-cuffed. The authorities have not carried out meaningful assessments of the need to keep him serving his sentence under the “special regime”. Thus, their assessments did not involve an analysis of his psychological and physical state, or of his attitude and demonstrated willingness to change, and were not conducted by specially-trained personnel. 10.  As to the material conditions in which he has been kept since 24 January 2012, the applicant submitted that, although a toilet had been installed in his cell in August 2012, it stands at about 45 cm from his bed. As the toilet has not been separated from the rest of the space, he has had the intrusive feeling of living in a toilet. Given that the prison administration has been refusing to provide hygienic products for cleaning the toilet, such as brushes and washing products, the toilet has been unusable. The overall hygiene in the cell and the common spaces has been extremely poor, with cockroaches and rats roaming about. 11.  On 10 June 2011 the first instance court sentenced the applicant to a whole-life sentence, which was confirmed by the appellate court on 27 June 2013. The Supreme Court of Cassation upheld the whole-life imprisonment sentence in a final judgment of 21 May 2014. 12.  The applicant submitted, and the Government did not comment on, that he has been kept in a permanently locked cell in Pazardzhik Prison, isolated from the rest of the prison population and only allowed to communicate with other life prisoners during the one-hour daily physical exercise he took outside his cell. There has been no running water or toilet in his cell which measures less than 6 square metres. The hygiene in the cell has been very poor and there have been cockroaches and bed bugs, and the prison administration has done nothing to get rid of them. As there is no table in his cell the applicant has been eating over a newspaper spread over his bed. While the natural light which reached the cell has been extremely weak, the artificial light has been kept on throughout the night. The temperature in the cell was inadequate, fluctuating between extremes in the summer and winter.