In legal practice, the one-year rule generally refers to a limitation or restriction that applies for a period of 12 months from a specified event, such as contract formation, dismissal, accrual of a cause of action or death. It is not a single codified doctrine, but a descriptive label used in a range of contexts.Across England & Wales, Scotland, Northern Ireland and Ireland, “one-year rule” may describe: (i) limitation periods (for example, one-year time limits for defamation and malicious falsehood claims in the UK; short contractual limitation clauses requiring claims to be brought within a year); (ii) employment law time limits (e.g. minimum one year’s continuous service under older unfair dismissal regimes, or one-year windows for bringing particular statutory claims); and (iii) certain probate, inheritance and family law time limits (such as deadlines to bring dependency or provision claims).The term is therefore highly context‑specific and practitioners should identify the underlying statute, contract term, court rule or case law defining the particular one-year period, and calculate time strictly, given courts’ general reluctance to extend short limitation or procedural deadlines.