In legal practice, “special circumstances” describes factual situations that justify departure from the usual rule, time limit or procedural requirement. It is a flexible, context‑specific expression rather than a single, fixed legal concept, and appears in legislation, rules of court and case law across England and Wales, Scotland, Northern Ireland and Ireland.The phrase is commonly used where a court, tribunal or public body has a discretion to extend time, relax a statutory requirement, vary costs consequences, or grant an exceptional remedy. Whether special circumstances exist is fact‑sensitive and assessed objectively; they must be unusual or out of the ordinary, but need not be unique. Financial hardship, serious illness, procedural confusion caused by the authority, or manifest injustice may, depending on the context, amount to special circumstances.Courts in all four jurisdictions apply similar principles: the decision-maker considers the purpose of the relevant rule or statute, the degree of departure from the norm, prejudice to other parties, and the overall interests of justice. Case law in specific areas (for example, costs, insolvency, tax, limitation and judicial review) provides tailored guidance on when special circumstances will, and will not, be found.