Trial of Lord George Gordon
The trial of Lord George Gordon for high treason occurred on 5 February 1781 before Lord Mansfield in the Court of King's Bench, as a result of Gordon's role in the Gordon Riots. Gordon, President of the Protestant Association, had led a protest against the Papists Act 1778, a Catholic emancipation bill.
Source: Wikipedia — Trial of Lord George Gordon (CC BY-SA 4.0)