People with disabilities are disproportionately over-represented as suspects of crime throughout the world, and experience greater barriers within the pre- and post-trial criminal process than suspects without disabilities. Evidence suggests that police officers are increasingly coming into contact with persons with disabilities and are acting as gatekeepers to mental health services, earning them the moniker "psychiatrists in blue.” People with serious psychosocial disabilities are also more likely to experience stigma on the basis of their impairment, which may influence police officers’ attitudes and treatment of persons with disabilities. This thesis will analyse the current barriers to justice for suspects with intellectual and psychosocial disabilities within the Irish pre-trial process; from the initial arrest, through to their detention in police custody and police interrogation. From the initial contact with the police, the pre-trial process presents many critical obstacles for suspects with psychosocial disabilities. The outcomes associated with these obstacles often have dramatic and lasting effects on subsequent trial proceedings and ultimate determinations of guilt or innocence. The objective of this thesis is to examine the existing laws and policies relating to persons with disabilities who have been arrested and to assess the accommodations in place to ensure their right of equal access to justice and secure their effective participation in the criminal and trial processes. It will demonstrate that the human rights provisions contained in the UN Convention on the Rights of Persons with Disabilities can play a critical role in informing and shaping criminal justice reforms in Ireland, with particular regard to the right of Access to Justice as provided under Article 13. This thesis will also draw upon comparative laws and practices, particularly from England and Wales, with a view towards identifying models of best practice which could be adopted in Ireland.