Three days of rioting in Tonypandy during a mining dispute resulted in one death. Armed English troops and police reinforcements were sent in by Winston Churchill to quell the trouble. Churchill's name has been mud in South Wales ever since.
Seamen's dispute/anti-Chinese disturbances (1911)
English police and troops had to be drafted into the city during a seamen's dispute. Things took a turn for the worse when bosses tried to introduce Chinese blackleg labour from Liverpool - the result, every Chinese laundry in Cardiff was attacked making it the most widespread disturbance in the city's history.
Race Riot (1919)
A race riot erupted at Cardiff Docks lasting 3 nights and resulting in the deaths of 3 men. Similar shameful disturbances also broke out at Barry and Newport.
Anthracite Strike (1925)
A riot at Ammanford during a strike by anthracite miners saw workers taking control of the town for 10 days. 200 Glamorgan police were ambushed by strikers at Pontamman Bridge during the so-called Battle of Ammanford.
Point Colliery (1929)
More than 700 people rioted at Cwmfelinfach, Gwent, over the employment of blackleg labour at Nine Mile Point Colliery.
In 1931 a disturbance broke out when miners attempted to prevent a family from being evicted from a property in Maerdy. 29 men and 4 women were subsequently arrested and sentenced to hard labour for unlawful assembly and incitement to riot.
A riot at Bedlinog during a mining dispute in October 1935 lead to Britain's largest ever mass trial at Cardiff in 1936. 53 men and 3 women were sentenced.
Riot at Tonypandy (1936)
Over 2000 people turned up in Tonypandy to protest against a fascist meeting held by Oswald Mosley's Blackshirts. The anti-fascist demonstration turned violent with 6 men and 1 woman receiving jail sentences.
Youth Riot (1966)
Approximately 100 youths from Cardiff (including a large contingent of girls) "invaded" Caerphilly seeking retribution for a remark made at a youth club the previous week. The Cardiff mob were met by approximately 200 Caerphilly/Valleys youths and an almighty scrap ensued. There were only 27 arrests because the local police didn't have the manpower to arrest any more - they also failed in their attempt to seal off the town. Knuckledusters and pick axes were used in the brawl.
A dispute between rival shopkeepers, the hot weather and youth unemployment were said to be the underlying causes of four nights of rioting in the Ely district of Cardiff. The infamous incident is known locally as the Ely Bread Riots.