Unlawful assembly is a legal term to describe a group of people with the mutual intent of deliberate disturbance of the peace. If the group are about to start the act of disturbance, it is termed a rout; if the disturbance is commenced, it is then termed a riot. In Britain, the offence was abolished in 1986.
By the 19th century, unlawful assembly was the term used in English law for an assembly of three or more persons with intent to commit a crime by force, or to carry out a common purpose (whether lawful or unlawful), in such a manner or in such circumstances as would in the opinion of firm and rational men endanger the public peace or create fear of immediate danger to the tranquillity of the neighbourhood. In the Year Book of the third year of Henry VII's reign assemblies were referred to as not punishable unless in terrorem populi domini regis. It was suggested[a] that legislation first became necessary at a time when it was usual for those landed proprietors who were on bad terms with one another to go to market at the head of bands of armed retainers.[b] An assembly, otherwise lawful, was not made unlawful if those who take part in it know beforehand that there will probably be organized opposition to it, and that it may cause a breach of the peace.[c] All persons may, and must if called upon to do so, assist in dispersing an unlawful assembly.[d] An assembly which was lawful could not be rendered unlawful by proclamation unless the proclamation was one authorized by statute.[e] Meetings for training or drilling, or military movements, were unlawful assemblies unless held under lawful authority from the Crown, the Lord Lieutenant, or two justices of the peace.[f]
An unlawful assembly which has made a motion towards its common purpose was termed a rout, and if the unlawful assembly should proceed to carry out its purpose, e.g. begin to demolish a particular enclosure, it became a riot. All three offences were misdemeanours in English law, punishable by fine and imprisonment. The offence was abolished by the Public Order Act 1986.
The common law as to unlawful assembly extended to Ireland, subject to special legislation. The law of Scotland included unlawful assembly under the same head as rioting.
Section 144 is a section of the Code of Criminal Procedure, which prohibits assembly of five or more persons, holding of public meetings, and carrying of firearms and can be invoked for up to two months. It also gives the magistracy the power to issue order absolute at once in urgent cases of nuisance or apprehended danger. With the introduction of Dhaka Metropolitan Police (DMP) in 1976, Section 144 has ceased to operate in the metropolitan jurisdiction in Bangladesh.
Under Part II of the Canadian Criminal Code (Offences Against Public Order), Unlawful Assemblies and Riots is when the assembly of three or more persons who cause fear and on reasonable grounds disturb peace in the neighborhood is against the law.
The Public Order Ordinance (chapter 245 of the laws of Hong Kong) defines "unlawful assembly" (§18) as an assembly of three or more persons conducting themselves in a "disorderly, intimidating, insulting or provocative manner intended or likely to cause a person reasonably to fear that the persons so assembled will conduct a breach of the peace or will by such conduct provoke other persons to commit a breach of the peace". Persons taking part in unlawful assemblies can be punished with up to five years imprisonment (if indicted) or a level 2 fine (HK$5000) and imprisonment for two years (on summary conviction).
Section 144 of the Criminal Procedure Code (CrPC) of 1973 empowers an executive magistrate to prohibit an assembly of more than four people in an area. According to sections 141-149 of the Indian Penal Code (IPC), the maximum punishment for engaging in rioting is rigorous imprisonment for 3 years and/or fine. Every member of an unlawful assembly can be held responsible for a crime committed by the group. Obstructing an officer trying to disperse an unlawful assembly may attract further punishment.
In about 1861, Officer Raj-Ratna E.F. Deboo IPS was the designer and architect of section 144, which reduced overall crime in that time in the State of Baroda. He was recognized for his initiative and awarded a gold medal by the Maharaja Gaekwad of Baroda for putting Section 144 in place and reducing overall crime.
The section was used for the first time in 1861 by the British Raj, and thereafter became an important tool to stop all nationalist protests during the Indian independence movement, and its use in independent India remains controversial as little has changed. It is often used to prevent protests or demonstrations, even the law doesn't use the terms, though it does mention "riot".