6.  The applicant was born in 1957. He is currently serving a life sentence in Pleven, following the commutation of the death penalty to which the courts sentenced him. 7.  An initial application lodged by the applicant led to the finding of a violation of Article 3 of the Convention because of the severity of the regime and conditions of detention imposed on him in Sofia prison between 1990 and 1998 (Iorgov v. Bulgaria, no. 40653/98, 11 March 2004). The present case concerns events subsequent to the commutation of the applicant's death penalty in 1999 to one of life imprisonment and his transfer to Pleven prison. 8.  Between 1976 and 1987 the applicant was convicted on one count of rape, two of robbery, one of aggravated robbery and one of disturbing public order (хулиганство). As a result he was given three prison sentences and spent a total of eight years and eight months in prison before being released on 14 March 1989. 9.  On 4 August 1989 he was arrested near the border between Bulgaria and Yugoslavia. In the course of the ensuing investigations he confessed to having murdered three minors not far from his town, Gulyantsi, on 17 July 1989, and explained that he had intended to leave the country illegally in order to avoid conviction. On 8 August 1989 he was remanded in custody. 10.  In the criminal proceedings against him he was charged with the murder of the three children, aged 12, 10 and 8 respectively, with the attempted rape of one of the three victims, with attempting to leave the country illegally and with four counts of trespassing followed by rape committed between 1984 and 1989. In a judgment of 9 May 1990 the Pleven Regional Court found him guilty of the murder of the three children, of the attempted rape of one of the victims, of attempting to leave the country illegally, and of rape committed in 1984 after unlawful entry into the victim's home. 11.  On the strength of the evidence produced, the court established the circumstances of the the triple murder as follows. The applicant, a lorry driver, had known the three victims because he had spent some time with their families on a festive occasion. On 17 July 1989 he was asked to transport part of the harvest from the fields around Gulyantsi. That afternoon he chanced upon the three children playing by a river not far from the town. He persuaded them to get into his lorry and drove them to a wood ten kilometres away. There, he tied up the youngest two and tried to rape the girl, who was 12 years old. Then, fearing that they would report him, he strangled the children one by one. To make sure they were dead, he kicked each child in the head several times and slit their throats with a knife. The same day he returned to the scene of the crime and buried the three bodies. 12.  The court sentenced him to death for the murder of the three children, considering that, under the circumstances, that was the only penalty that fulfilled the purpose of criminal repression set forth in Article 36 of the Criminal Code: this was an exceptionally serious crime, with several aggravating circumstances (the victims were all young children and had been killed in a particularly cruel manner in order to cover up another crime – the rape of one of them), and the accused had already been convicted of other crimes, but the sentences he had served had not had the desired deterrent effect. The court's decision was upheld by the Supreme Court on 24 October 1990. The applicant then submitted a request for the revision of the judgment, which was rejected on 8 April 1994. 13.  The last executions of convicts sentenced to death in Bulgaria took place in November 1989. On 20 July 1990 the National Assembly placed a moratorium on all executions of prisoners sentenced to death. On 23 December 1998 the National Assembly abolished capital punishment and replaced it in the Criminal Code with a new penalty, life imprisonment without commutation (доживотен затвор без замяна). By a decree of 25 January 1999, the Vice-President of Bulgaria commuted the death sentences of the 19 convicts who had been awaiting execution since the introduction of the moratorium, including the applicant, to sentences of life imprisonment without commutation. 14.  On 3 November 2009, when news of the parties was last received, the applicant was still in Pleven prison. He had already served twenty years and three months of his life sentence. 15.  On 27 April 1999 the applicant was transferred to Pleven prison. In a decision of 5 July 1999 the Veliko Tarnovo Court of Appeal ordered him to be placed under the strictest regime, the “special regime”. It based its decision on section 127b of the Execution of Sentences Act. 16.  The applicant was placed in the section of the prison reserved for prisoners serving life sentences, located on the third floor and separated from the rest of the building by a locked door. It comprised six cells, a corridor and a bathroom with lavatories. 17.  Each cell measured 4.50 m² and was separated from the neighbouring cells by two solid metal panels, and from the corridor by iron bars. The dividing panels jutted out about 30 inches past the bars, making visual contact between the prisoners impossible. Each cell had a metal bed and bedside table. A metal plate welded to the bars served as a table and another, welded to the bed served as a bench. There was a shelf on the wall for the detainees' clothes. 18.  The only daylight came from the windows in the corridor, which were too small to provide sufficient light or ventilation. There was a fluorescent lamp, controlled by the warder, on the ceiling outside each cell. At night light was provided by a 60-watt electric bulb fixed to the end of the metal partition panel, out of reach of the detainees. It was left on all night, but the light it gave out was not bright enough to read or write by. There was a window in the bathroom, but it was covered with a metal plate. Heating was provided by radiators attached to the corridor walls, about two yards from the cell bars. 19.  The applicant went to shower once a week, and that was his only access to hot water. He was allowed to use the sanitation facilities in his detention quarters three times a day. The rest of the time he had to use a plastic bucket as a toilet. 20.  The applicant had the right to one hour's exercise in the open air per day. Until the beginning of 2002 prisoners serving life sentences were taken out for their open-air exercise one by one, handcuffed and escorted by guards. It was then decided to take them out two at a time, still in handcuffs, and after a while the use of handcuffs was dropped. In 2002 the applicant and the other prisoners serving life sentences were allowed to play table tennis once a week in the activity room adjacent to their quarters. They were also allowed to watch a film and see a priest once a week. From 18 October 2000 onwards the prison authorities allowed the applicant to work in his cell, folding envelopes. 21.  In October 2003, at the applicant's initiative, the prison governor took certain steps to improve the detention conditions of prisoners serving life sentences: the cells were left open between 5.30 a.m. and 8 p.m., allowing the prisoners to communicate and to use the lavatory when necessary, and giving them access to running water. The metal plate over the bathroom window was removed to let the daylight in. The electric light bulbs were moved closer to the cells and the metal wall by the applicant's bed was covered with insulating material. 22.  In 2003 and 2004 the applicant's detention regime was relaxed twice in succession. On 6 April 2004 he joined a group of ordinary prisoners and left the quarters reserved for prisoners serving life sentences. Since that date he has been sharing a 23 m² cell with five other prisoners. The door of the cell is left open in the daytime and he can talk to the other prisoners in his group in the corridor. 23.  According to a report by the Director General of Prison Administration presented by the Government, the applicant regularly took part in sporting activities (table tennis, football, volleyball) and in the organisation of various concerts and festivities on national holidays, at Easter and over the Christmas season. He regularly spoke to his close relatives on the telephone and received parcels from them. Since 2 April 2007 he has worked as a cleaner in charge of the cells on the third floor of the prison. 24.  The applicant suffers from back pain (discopathy), for which he was treated in hospital in 2000. According to him, the pain subsequently grew worse and on 13 February 2002 he was examined by a doctor, who recommended physiotherapy. He received no such treatment and complained about it to the Minister of Justice. In a letter of 4 April 2002 the Director General of Prison Administration informed the applicant that the treatment recommended was not the usual method for treating his condition and, as he was under medical supervision, medicine could be administered to him in Pleven prison. 25.  According to a report by the director of the prison's medical centre, presented by the Government, the applicant consulted neurology specialists about his back pains on several occasions. In 2003 he apparently underwent thorough medical examinations which revealed no complications. 26.  In March 2003, following a skin infection, the applicant underwent surgery at the Sofia prison hospital. He was there from 15 March to 18 April 2003. The doctors noted an improvement in his health by the time he left the hospital. The applicant says that since he was transferred to a shared cell he has had no particular health problems. 27.  According to the report by the director of the prison's medical centre, the applicant consulted the prison dentist over a hundred times for different types of dental treatment between 1999 and 2004.