Taxing power refers to the legal authority of a state or public body to impose, assess and collect taxes. In UK and Irish legal practice it is a descriptive term, rather than a single defined statutory concept, and is derived from constitutional and legislative frameworks that confer power to raise revenue.In England and Wales, Scotland and Northern Ireland, Parliament at Westminster holds primary taxing power, exercised through Finance Acts and other tax legislation, with certain devolved taxing powers granted to the Scottish Parliament, Senedd Cymru and the Northern Ireland Assembly. In Ireland, taxing power is vested in the Oireachtas under the Constitution, implemented through annual Finance Acts and other tax statutes.The concept is central to public law, constitutional law and tax law, informing challenges to the validity of taxes, the limits of delegated legislation, and disputes over the scope of devolved or local authority fiscal powers. Taxing power is also relevant when advising on state aid, double taxation agreements, fiscal sovereignty, and the interpretation of taxing statutes, including the principle that taxes must be clearly authorised by legislation. Usage is broadly consistent across the UK and Ireland.