Employment describes a contractual working relationship in which an individual personally performs work or services for another (usually a business) in return for wages or salary, and is subject to the other party’s control and direction. It underpins rights and obligations in employment law, tax, social security and pensions.Across England & Wales, Scotland and Northern Ireland, “employee” and “worker” are defined primarily in statute (for example, the Employment Rights Act 1996 and related legislation), interpreted and refined by extensive case law on control, mutuality of obligation and integration into the business. In Ireland, definitions are drawn from legislation (including the Terms of Employment (Information) Acts) and common law tests, with a similar focus on the substance of the relationship rather than labels.Employment status is distinct from self‑employment and from agency, casual or gig arrangements, although tribunals and courts regularly examine such relationships to determine whether employment exists in substance. Establishing employment is critical for access to statutory employment rights, unfair dismissal protection, redundancy payments, minimum wage, working time protections, vicarious liability, PAYE, PRSI/NI contributions and collective labour law protections across the UK and Ireland.