Arson refers in practice to the deliberate or reckless setting of fire to property, usually with intent to damage, endanger life, or defraud. It is a serious offence attracting custodial sentences and often arises in criminal, insurance and civil liability contexts. In England and Wales, “arson” is not a standalone statutory label but commonly describes criminal damage by fire under the Criminal Damage Act 1971, including aggravated arson where life is endangered. Case law and charging practice use “arson” to distinguish fire‑related criminal damage from other forms. In Scotland, arson is not a technical term; equivalent conduct is prosecuted mainly as wilful fire‑raising or culpable and reckless fire‑raising at common law, with different levels of seriousness depending on risk to life and extent of damage. In Northern Ireland, arson is generally charged under provisions corresponding to the Criminal Damage Act 1971, and the term is used similarly to England and Wales. In Ireland, arson is primarily governed by the Criminal Damage Act 1991, which criminalises damaging property by fire and creating risk to life. Across all jurisdictions, issues of intent, recklessness, endangerment of life, insurance fraud, and evidential complexity (e.g. expert fire investigation) are central.