The Hay-loft Plot of Thistlewood and his 24 Conspirators at 8 o'clock in Cato Street Edgeware Road, London

The Cato Street Conspiracy was one of the most dramatic episodes in the turbulent history of radical politics in early 19th-century London.

On 23 February 1820, a group of radicals, led by Arthur Thistlewood, assembled in a hay loft at 6 Cato Street, where they were plotting to assassinate the entire cabinet. Inspired by revolutionary ideas about human rights, their intention was to slaughter the politicians as they dined at Lord Harrowby's house in Grosvenor Square, seize power and declare a provisional government.

This etching is a representation of the events of that night, which took place only a short distance from Grosvenor Square. Thirteen police officers stormed the loft but members of the gang refused to surrender their weapons and a battle ensued. Policeman Richard Smithers, seen here on the right by the trap door, was stabbed by Thistlewood and died.

The annotated print has a key at the bottom indicating the main participants in the scene: the conspirators are labelled by letters while the police officers, led by George Ruthven, are denoted by numbers. Thistlewood exclaims 'Extinguish the lights!' as the conspirators prepare to make a get-away.

Two of the conspirators are shown attempting to climb out of windows, and four men did actually escape that way. However, they were later caught and arrested. Only a few days later, members of Thistlewood's gang were found guilty of high treason and some were sentenced to death, while others were imprisoned for life. The ringleader Thistlewood was executed at Newgate Prison in May 1820.