In 1778, parliament had passed the Relief Act which repealed harsh anti-Catholic legislation from the seventeenth century. In June 1780, violent anti-Catholic riots broke out in London as Lord George Gordon marched on parliament to present a petition requesting the repeal of the Relief Act and a return to Catholic repression. (Edinburgh and Glasgow had already seen similar riots).Chapels, known Catholic houses, prisons, public buildings and even Catholics in the street were attacked. There were running battles between the demonstrators and the authorities.It took the government and London authorities ten days to restore order in the capital.
By that time, 12,000 troops had been deployed and over 700 had been killed. Gordon was tried for high treason but acquitted. The Lord Mayor of London was fined £1,000 for negligence of his duties.