Self-incrimination refers to a person exposing themself, directly or indirectly, to criminal liability through their own statements, documents, acts or omissions, for example when giving evidence, answering police questions or complying with investigatory powers. Across England & Wales, Scotland, Northern Ireland and Ireland, the concept underpins the privilege against self-incrimination, closely linked to the right to a fair trial and the presumption of innocence. It arises in criminal proceedings, regulatory investigations, civil disclosure and inquiries. The privilege is principally shaped by case law and human rights instruments (notably Article 6 ECHR), and is reflected in statutory provisions such as the Police and Criminal Evidence Act 1984 (and equivalent legislation), compulsory interview regimes, and investigative powers with use and derivative-use immunity. Key issues for practitioners include: when a person can refuse to answer questions; the admissibility of compelled answers; inferences from silence; protections for suspects, accused persons and witnesses; and limits to the privilege (e.g. production of pre-existing documents, company records). Usage and core principles are broadly consistent across the UK and Ireland, though detailed procedural rules and statutory frameworks vary by jurisdiction and context.