A police riot is a riot carried out by the police; a riot that the police are responsible for instigating, escalating or sustaining as a violent confrontation; an event characterised by widespread police brutality; a mass police action that is violently undertaken against members of the public for the purpose of political repression. The term "police riot" was first used in the Walker Report investigating the events surrounding the 1968 Democratic National Convention in Chicago to describe the "unrestrained and indiscriminate" violence that the police "inflicted upon persons who had broken no law, disobeyed no order, made no threat." In this sense a police riot refers to rioting carried out by the police (or those acting in a police capacity) rather than a riot carried out by people who may be motivated to a greater or lesser degree by grievances with the police (see the 1981 Toxteth riots or the 1992 Los Angeles Riots for examples of riots over policing rather than police riots).
United States 
Haymarket Riot 
During the early years of labor union organizing, police violence was frequently used in efforts to quell protesting workers. One notable incident took place in May 1886, when police killed four striking workers at the McCormick Harvesting Machine Co. in Chicago. The following day, a peaceful demonstration in Haymarket Square erupted in violence when a bomb was thrown, killing eight policemen — an event known as the Haymarket Riot. Fifty years later, in July 1934, police in San Francisco were involved in several encounters with striking longshore workers. After two picketers were killed, the other area unions joined together and called a general strike of all workers (the "Big Strike"). Subsequent criticism of the police was probably the occasion for the coining of the term "police riot."
Vietnam War protests 
During the Vietnam War, anti-war demonstrators frequently clashed with police, who were equipped with billy clubs and tear gas. The demonstrators claimed that the attacks were unprovoked; the authorities claimed the demonstrators were rioting. The most notorious of these assaults, which was shown on television and which included national television reporters in the mayhem, took place during the August 1968 Democratic National Convention in Chicago, which was the scene of massive anti-war street protests. The actions of the police were later described as a police riot by the Walker Report to the US National Commission on the Causes and Prevention of Violence.
Tompkins Square Park police riot 
In August 1988, a riot erupted in Tompkins Square Park in the Lower East Side New York when police, some mounted on horseback, attempted to enforce a newly passed curfew for the park. Bystanders, artists, residents, homeless people, reporters, and political activists were caught up in the police action that took place during the night of August 6–7. Videotape evidence, provided by onlookers and participants, showed seemingly unprovoked violent acts by the police, as well as a number of officers having covered up or removed their names and badge numbers from their uniforms. The footage was broadcast on local television, resulting in widespread public awareness. In an editorial The New York Times dubbed the incident a "police riot." The incident became known as the Tompkins Square Park Police Riot.
1999 Seattle Protests 
The term police riot has been applied to events such as the Seattle W.T.O. protests, where police clad in riot gear used clubs, tear gas and projectiles to disperse groups of protesters, anarchists and direct action anti-capitalists.
United Kingdom 
Battle of the Beanfield 
During an attempt to enforce an exclusion zone around Stonehenge, Wiltshire, in 1985, the police entered the field where a group of travellers known as the Peace Convoy were being detained and began smashing the vehicles and beating the occupants. The travellers eventually sued the Wiltshire police force for wrongful arrest, assault and criminal damage.
See also 
- Black Act
- Demonstration (people)
- Police brutality
- Black bloc
- Street fighting
- Stonewall riots
- White Night riots: After the Dan White verdict prompted rioting at San Francisco City Hall, police attacked the Castro district, two hours later and a mile away.
- WTO Ministerial Conference of 1999 protest activity
- 2008 Republican National Convention: Police raids and arrests
- 2010 Thai political protests
- 2013 Bangladesh riot
- Cedar Avenue Valentines Police Riot
- skullthump.com: a collection of videos from riots as posted on YouTube
- police at riots an archive of riots between police and protestors around the world.
- Summary of the Walker Report, http://www.fjc.gov/history/home.nsf/page/tu_chicago7_doc_13.html
- Walker, Samuel (1977). A Critical History of Police Reform: The Emergence of Professionalism. Lexington, Massachusetts: Lexington Books. p. 147. ISBN 978-0-669-01292-7.
- Walker Report summary, The Chicago Seven Conspiracy Trial Historical Documents Federal Judicial Center
- "Yes, a Police Riot," editorial of The New York Times, August 26, 1988, Section A; Page 30, Column 1; Editorial Desk
- Ed. Andy Worthington, 2005, The Battle of the Beanfield, Enabler Publications, ISBN 0-9523316-6-7
- The Battle of the Beanfield