What is "black and tans"

n. Royal Irish Constabulary Reserve Force, which was one of two paramilitary forces employed by the Royal Irish Constabulary from 1920 to 1921, to suppress revolution in Ireland.

The Black and Tans , officially the Royal Irish Constabulary Special Reserve, was a force of Temporary Constables recruited to assist the Royal Irish Constabulary (RIC) during the Irish War of Independence. The force was the brainchild of Winston Churchill, then British Secretary of State for War. Recruitment began in Great Britain in late 1919. Thousands, many of them British Army veterans of World War I, answered the British government's call for recruits. Most of the recruits came from Britain, although it also had some members from Ireland. Their role was to help the RIC maintain control and fight the Irish Republican Army (IRA), the army of the Irish Republic. The nickname "Black and Tans" arose from the colours of the improvised uniforms they initially wore, composed of mixed khaki British Army and rifle green RIC uniform parts. The Black and Tans became infamous for their attacks on civilians and civilian property.

The Black and Tans were sometimes confused with the Auxiliary Division, a counter-insurgency unit of the RIC made up of former British officers. However, sometimes the term "Black and Tans" is used to cover both of these groups.