Other international sources used in drafting the Guidelines include Guidelines of the Committee of Ministers of the Council of Europe on eradicating impunity for serious human rights violations,12 the ICCPR and UNCAT, as well as the observations, general comments and jurisprudence of their treaty bodies, the HRC and the CAT. The set of specific standards known as the Manual on the Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (the “Istanbul Protocol”) is of particular importance since it deals with assessing, documenting and investigating allegations of ill-treatment. It is also referred to in the Court’s judgments.13 These international instruments often leave implementation to the state, but the frameworks they establish provide a basis for their incorporation into domestic law. Some are even directly applicable to particular persons and situations, and so the need for guidance on the standards they contain is crucial. I. The origins of the obligation to investigate ill-treatment 1.1 The absolute prohibition of ill-treatment 1.1.1 The use of torture or inhuman or degrading treatment or  punishment is absolutely prohibited in all circumstances. No  derogation from this prohibition is permissible. The absolute and non-derogable nature of the prohibition of ill-treatment is clear from the text of the ECHR. Article 3 provides that “[n]o one shall be subjected to torture or to inhuman or degrading treatment or punishment” and Article 15(2) states that “[n]o derogation from Article 2, except in respect of deaths resulting from lawful acts of war, or from Articles 3, 4 (paragraph 1) and 7 shall be made under this provision.” This is also reflected in the standard wording used by the Court in Article 3 cases: “As the Court has stated on many occasions, Article 3 enshrines one of the most fundamental values of democratic societies. Even in the most difficult circumstances, such as the fight against terrorism and organised crime, the Convention prohibits in absolute terms torture and inhuman or degrading treatment or punishment. Unlike most of the substantive clauses of the Convention and of Protocols Nos. 1 and 4, Article 3 makes no provision for exceptions and 12. Adopted by the Committee of Ministers of the Council of Europe on 30 March 2011 at the 1110th meeting of the Ministers’ Deputies. See appendix 5 of the current publication. 13. Bati and Others v. Turkey, Judgment of 3 June 2004, applications nos. 33097/96 and 57834/00, para. 100. Effective investigation of ill-treatment – Guidelines ► Page 18