The 1919 Battle of George Square, also known as Bloody Friday and Black Friday, was one of the worst riots on the streets of Glasgow, Scotland, which took place on Friday, January 31, 1919 . The dispute revolved around a campaign for shorter working hours, backed by widespread strike action. Clashes between police and protesters broke out, and led to the Government sending soldiers to the city to prevent any further gatherings due to their fear of a left-wing workers revolution, described as a "Bolshevist uprising" by the then Secretary of State for Scotland , as had happened the previous year in the 1917 Russian Revolution and was occurring in Germany whilst the 40 Hours strike unfolded .