The early 20th century in Ireland was dominated by Irish nationalists' pursuit of Home Rule from the United Kingdom. The Ulster Special Constabulary, was founded to reinforce the RIC in Northern Ireland. Some sources say the Black and Tans were officially named the "RIC Special Reserve", but this is denied by other sources, which say they were not a separate force but "recruits to the regular RIC" and "enlisted as regular constabulary". However, sometimes the term "Black and Tans" covers both groups. The Black and Tans were sometimes confused with the Auxiliary Division, a counter-insurgency unit of the RIC, also recruited during the conflict and made up of former British officers.
Their actions further swayed Irish public opinion against British rule and drew condemnation in Britain. The Black and Tans gained a reputation for brutality and became notorious for reprisal attacks on civilians and civilian property, including extrajudicial killings, arson and looting. By 1921, Black and Tans made up almost half of the RIC in County Tipperary, for example. They served in all parts of Ireland, but most were sent to southern and western regions where fighting was heaviest. The nickname "Black and Tans" arose from the colours of the improvised uniforms they initially wore, a mixture of dark green RIC (which appeared black) and khaki British Army. They were to help the overstretched RIC maintain control and suppress the Irish Republican Army (IRA), although they were less well trained in ordinary policing. The British administration in Ireland promoted the idea of bolstering the RIC with British recruits. Some sources count a small number of Irishmen as 'Black and Tans'. The vast majority were unemployed former British soldiers from Britain who had fought in the First World War. Recruitment began in Great Britain in January 1920 and about 10,000 men enlisted during the conflict. The Black and Tans ( Irish: Dúchrónaigh) were constables recruited into the Royal Irish Constabulary (RIC) as reinforcements during the Irish War of Independence.
A Black and Tan in Dublin, smoking and carrying a Lewis gun, February 1921