5.  The applicant was born in 1972 and is at present detained in Bobov dol Prison. 6.  Criminal proceedings for murder were opened against him on 11 January 2000. They continued until 27 November 2003 when he was convicted and sentenced to life imprisonment by means of a final judgment of the Supreme Court of Cassation. 7.  From 8 March 2000 to 5 November 2008 the applicant was detained in Lovech Prison, initially being held there in pre-trial detention and after 27 November 2003 as a prisoner serving a life imprisonment sentence. On 5 November 2008 he was transferred to Bobov dol Prison. 8.  On 4 August 2003 the applicant received a letter dated 1 August 2003 from the lawyer representing him in the criminal proceedings. The letter concerned the possible outcome of the proceedings and the strategy of the defence. The envelope had been opened and bore the signature of an official of the prison administration. 9.  After the conclusion of the domestic proceedings, between 12 January and 13 April 2004 the applicant received two more letters from the same lawyer and two letters from another lawyer. All four envelopes had been opened and bore the signatures of officials of the prison administration. 10.  On 10 December 2003 the applicant received a letter from the Registry of the Court, dated 2 December 2003 and concerning his application in the present case. The envelope had been opened and bore the signature of an official of the prison administration. 11.  On 5 February and 16 April 2004 the applicant complained to the prison administration of the practice of opening and reading his letters. In reply, he was informed that the monitoring of detainees' and prisoners' correspondence was envisaged by section 33 of the Execution of Punishments Act, that it concerned all inmates and that it pursued “security-related” and “educational” aims.