Cato Street Conspiracy (1820): Plot to Murder the Cabinet

The Cato Street Conspiracy was a plot by a group of London radicals to murder the entire British cabinet at a dinner on 23 February 1820 and spark a revolution. Betrayed by a government spy, the conspirators were surrounded in a hayloft in Cato Street, Marylebone, that same evening. Five were later hanged and beheaded, among the last people in Britain to suffer that punishment.

Background

Britain after 1815 was troubled by economic hardship, unemployment and demands for political reform. Radical groups met in taverns and back rooms, and some followers of the reformer Thomas Spence, known as Spenceans, called for the land to be held in common and talked openly of revolution.

Arthur Thistlewood, a former soldier and Spencean, had already been charged with high treason after the Spa Fields riots of 1816, but the case against him was dropped after a fellow accused, James Watson, was acquitted in 1817. The killing of peaceful protesters at the Peterloo Massacre in August 1819, and the repressive Six Acts that followed, convinced him and a small circle of followers that only violence could bring change. The death of King George III on 29 January 1820 added to the sense of political crisis.

The plot

Among Thistlewood’s associates was George Edwards, who was in fact a paid informer for the Home Office. Edwards encouraged the group’s most extreme plans and kept the authorities informed.

In February 1820 the plotters learned from an announcement in the New Times newspaper that the cabinet would dine at the house of Lord Harrowby, the Lord President of the Council, in Grosvenor Square on 23 February. They planned to burst in, kill the ministers and, according to evidence at their trial, cut off the heads of Lord Castlereagh and Lord Sidmouth, the most hated members of the government. They then hoped to seize cannon and the Bank of England and proclaim a provisional government. The dinner, however, was not actually taking place.

The raid in Cato Street

On the evening of 23 February about two dozen conspirators gathered with weapons in a hayloft above a stable in Cato Street, off Edgware Road. A party of Bow Street officers, led by George Ruthven and directed by the magistrate Richard Birnie, climbed the ladder to arrest them before soldiers arrived.

In the struggle the candles were put out, shots were fired and Thistlewood ran through officer Richard Smithers with a sword, killing him. Thistlewood and several others escaped in the confusion, but a detachment of the Coldstream Guards arrived and arrested nine men on the spot. Thistlewood was caught the next morning at a house in Moorfields.

The conspirators were mostly working men from London’s trades, including shoemakers, a butcher and a cabinet-maker, many of them poor and out of work. Historians still debate how far the plot would have gone without Edwards, who supplied money and arms and pressed for action, but there is no doubt that Thistlewood was determined on violence.

Trial and execution

The prisoners were tried for high treason at the Old Bailey in April 1820. Some of the arrested men turned King’s evidence and testified against the others, while Edwards himself was kept out of court and later left the country. The defence argued that the plot had been driven by the spy, but the jury convicted.

On 1 May 1820, Arthur Thistlewood, William Davidson, James Ings, John Brunt and Richard Tidd were hanged outside Newgate prison before a large crowd. The traditional sentence for treason, which included drawing and quartering, had been reduced, but their heads were cut off after death and shown to the crowd. Five other conspirators were transported to Australia for life.

William Davidson, born in Jamaica, the son of a white official and a Black mother, is now often remembered as one of the early Black radicals in British history.

Legacy

The conspiracy allowed the government to present itself as the defender of order against violent revolution, and for a time it discredited the radical cause. Yet the role of George Edwards was exposed in Parliament and the press, adding to public distrust of government spies.

Most reformers drew the lesson that change would come through petitions, the press and Parliament rather than conspiracy. That path eventually led to the Great Reform Act of 1832. The building in Cato Street still stands and is marked by a plaque.

Timeline

• 1816, December: Thistlewood is involved in the Spa Fields riots in London.
• 1819, 16 August: The Peterloo Massacre in Manchester.
• 1820, 29 January: King George III dies.
• 1820, 23 February: The conspirators are surrounded in Cato Street; officer Richard Smithers is killed.
• 1820, 24 February: Thistlewood is arrested in Moorfields.
• 1820, April: The conspirators are tried for high treason at the Old Bailey.
• 1820, 1 May: Five men are hanged and beheaded outside Newgate.

Why it matters

The Cato Street Conspiracy marked the violent extreme of post-war radicalism in Britain. Its failure, and the revelation that a government spy had helped drive it, shaped the debate over both revolution and state surveillance in the years before the Reform Act.