Evasion of tax refers to deliberate, dishonest conduct to reduce or avoid a tax liability, typically by concealing income, falsifying records, or misrepresenting facts to HMRC (UK) or Revenue (Ireland). It is distinct from lawful tax avoidance, which involves arranging affairs within the tax legislation.In the UK and Ireland, “tax evasion” is a descriptive term rather than a single codified offence. It encompasses a range of criminal offences, including cheating the public revenue, fraudulent evasion of income tax, VAT or duties, and common law or statutory fraud. The concept is developed through a combination of statute and case law.Key features are intentional deception, knowledge of liability, and a purpose to secure an unlawful tax advantage. Negligent error or careless compliance, without dishonesty, will usually fall outside tax evasion and instead attract civil penalties.The term is used consistently across England and Wales, Scotland, Northern Ireland and Ireland, although the underlying offences, procedures and penalties differ by jurisdiction. It is central to criminal tax investigations, corporate criminal liability (including failure to prevent the facilitation of tax evasion), money laundering risk assessments and professional conduct obligations for advisers.