1. Introduction The following document sets out to provide an update to the main findings from a comprehensive review of policing oversight across the forty-seven Council of Europe States first set out in September 2015. The update reflects the position of police oversight mechanisms cross the forty-seven States as of 20 February 2017. In addition to the update this introductory chapter explores the recent history of police oversight in the Council of Europe, its origins in legislative and other supporting instruments, and its development in case law. The remainder of this chapter sets out the aims and objectives and the methodology employed to conduct the original research and that undertaken to inform the update. The remaining two chapters incorporate a revised country-by-country review of police oversight mechanisms, along with a critique of these approaches and an assessment of progress with a series of recommendations made in the original document. 1.1 Recent history of police oversight in the Council of Europe The development of Council of Europe standards on police oversight is mainly rooted in the absolute prohibition of torture or inhuman or degrading treatment or punishment given effect in Article 3 of the European Convention for the Protection of Human Rights and Fundamental Freedoms (ECHR). However, without an accompanying positive obligation on the State to investigate such treatment it is unlikely that principles or standards would have been developed and implemented. Whilst Article 3 has driven the development of police oversight, the influence of the Right to Life (Article 2 ECHR) on investigative mechanisms should not be underestimated. The resulting overarching principles of police oversight have enabled the implementation of oversight models in countries across the 47 member States, that to varying degrees deliver on their positive obligations. The State has a duty to take measures to prevent or punish infringements committed by its own agents or representatives. A series of obligations on 3