Needs five elements: (a) it must involve at least 12 persons (three at common law, 12 by the Public Order Act 1986 making it a criminal act); (b) all must have a common purpose; (c) there must have been an inception or execution of that common purpose; (d) they must intend to help one another by force if necessary against any person who may oppose them in the execution of their common purpose; (e) force or violence must be used in such a manner as to alarm at least one person of reasonable firmness and courage. This definition originated in Field v. Receiver of the Metropolitan Police (1907). Riot is often insured as an additional peril (linked with malicious persons) under property insurances.
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One of the extended coverage perils, related to, but broader than, civil commotion.

Any person suffering riot damage can claim compensation from the police authority but only to the extent that the compensation exceeds an insurance claim. Insurers who have paid a claim can exercise subrogation rights against the police in their own name.

Riot has an exact legal meaning. Riot and civil commotion are mentioned in the operative clause of the standard fire policy as excluded perils. Cover can be obtained as an additional peril, sometimes linked with damage caused by labour or political disturbances or vandals or malicious persons.

Group of perils added to a fire policy. Damage caused in these ways embraces fire damage and other forms of damage, e.g. wrecking and looting, but not losses caused by war and allied perils. The insured must give notice of claim within seven days to assist the subrogation rights of insurers in their claim against the police authority under the Riot (Damages) Act 1886 that allows 14 days for the particulars of the occurrence to be notified. The normal riot wording restricts damage caused maliciously to damage caused by malicious persons acting in connection with any political organisation. See MALICIOUS DAMAGE; TERRORISM.