An accessory before the fact is a person who intentionally assists, encourages or counsels another to commit a crime, but is not physically present when the offence is carried out. In practice, this covers conduct such as planning, providing information, supplying tools or weapons, or otherwise facilitating the principal offender’s actions in advance.In England and Wales and Northern Ireland, the concept is now largely absorbed into statutory provisions on secondary liability, principally under the Accessories and Abettors Act 1861 and related case law on aiding, abetting, counselling or procuring. The older expression “accessory before the fact” still appears in judgments and commentary, but modern indictments usually rely on general secondary participation language.In Scotland, the equivalent idea is addressed through the law of “art and part” liability, which similarly criminalises those who participate by prior assistance or encouragement, even if absent at the scene.In Ireland, the term continues to be used alongside statutory provisions and common law on secondary parties. Across all four jurisdictions, an accessory before the fact is generally punishable as if they were a principal offender, reflecting the seriousness of prior criminal involvement.