Cato Street Conspiracy: A Murder Plot

The Cato Street Conspiracy was a plot in 1820 to murder all of the British cabinet ministers and the Prime Minister, Lord Liverpool. It involved a group of discontent conspirators who were unhappy about various circumstances. These circumstances included the economy and the Peterloo Massacre (an event where approximately 80,000 people gathered to demand reform of parliamentary representation and the cavalry charged into the crowd killing as many as 15 and injuring up to 700).

Cato Street Conspiracy to Murder Robert Jenkinson, 2nd Earl of Liverpool, Courtesy of Wikipedia

Robert Jenkinson, 2nd Earl of Liverpool, Courtesy of Wikipedia

The conspirators were called the Spencean Philanthropists. They took their name from Thomas Spence, an English radical of the late eighteenth and early nineteen century who believed in common land ownership and was imprisoned for these beliefs. The Spencean Philanthropists had ” a view … [of] effecting a revolution by means of sanguinary violence.”[1]

The leader of the radical conspirators was Arthur Thistlewood. He was born a year before Jane Austen in Tupholme, Lincolnshire in 1774. He was apprenticed to a Newark apothecary before serving as a lieutenant in the militia, and although Thistlewood’s appearance was average, he had the appearance of a military man: He usually wore a long blue coat and blue pantaloons and was also described in the following manner:

“[F]ive feet ten inches high … a sallow complexion, long visage, dark hair, (a little grey), dark hazel eyes and arched eye-brows, a wide mouth and a good set of teeth … a scar under his right jaw.”[2]

GB-1647-x350a-Arthur Thistlewood

Arthur Thistlewood. Public domain.

Thistlewood had a record of getting into trouble. He was charged with sedition but acquitted, and he served a year in prison for challenging Lord Sidmouth, the Prime Minister at the time. In 1816, Thistlewood was also involved in the Spa Fields riot — a mass meeting that the Spenceans turned into a riot hoping to seize control of the government.

Henry Addington, 1st Viscount Sidmouth, Courtesy of Wikipedia

Henry Addington, 1st Viscount Sidmouth. Courtesy of Wikipedia.

Because of the Spencean’s beliefs and actions, the government was concerned about them. The government sent spies into their midst and learned they wanted to overthrow the government. Additionally, as Thistlewood had been concocting a plan to “assassinate the ministers, each in his own house,”[3] one of the government’s spies, George Edwards, offered Thistlewood some valuable information: Edwards pointed out to Thistlewood that “there was to be a cabinet dinner at the house of Earl Harrowby, President of the Council … on the 23rd of February.”[4] Thistlewood was thrilled and gleefully declared, “It will be a rare haul to murder them all together.”[5]

To accomplish the murders, some of the conspirators were tasked with various jobs, and it was claimed these jobs included the following:

“[One person was watching] Harrowby’s house; one was to call and deliver a dispatch-box at the door; … others were … to rush in, and having secured the servants, they were to assassinate the ministers as they sat at dinner; bringing away as special trophies, the heads of Lord Sidmouth and Lord Castlereagh, in two bags provided for the purpose!”[6]

To finalize Thistlewood’s diabolical plans, the conspirators met in a dilapidated three-stall stable in the hayloft. It was only accessible by ladder and had to be entered through a trap door. The stable was located near the Edgeware-road, which was intersected by an obscure street called Cato Street and “inhabited by persons in a humble class of life.”[7]

Leading the police effort was the chief magistrate of Bow Street, Richard Birnie, Esq. He was a native of Banff, Aberdeenshire, and born in about 1760. He had a police force of twelve men, known as the Bow Street Runners, who were London’s first professional police force and highly adept at surveillance.

Richard Birnie, Courtesy of Wikipedia

Richard Birnie. Courtesy of Wikipedia.

The Bow Street Runners easily observed the conspirators going about their business and did so in such a discreet fashion, they did not excite any notice among the conspirators. In fact, the Bow Street Runners’ movements were so unobtrusive and clandestine, “that until the discharge of fire-arms was heard, everything remained perfectly quiet.”[8] Accompanying the Bow Street Runners was the Coldstream Guards whose origins began with the English Civil War when Oliver Cromwell allowed Colonel George Monck to form his own regiment. The Coldstream Guards were from the Portman Street barracks.

At six o’clock everything was in readiness to arrest the conspirators. However, the Coldstream Guards had not yet arrived. They Bow Street Runners decided to enter and the first policeman through the trap door was a man named Richard Smithers. As the room was dimly lit, Smithers cried out to the conspirators that they should surrender as there was no hope they would escape. The conspirators refused, and, Thistlewood ran Smithers through with his sword, causing him to fall dead to the floor.

Cato Street Arrests, Public Domain

Cato Street Arrests. Public domain.

The lights were doused and a heated struggle ensued. “Some [conspirators] flung themselves down through the trap-door; others got out through a window,”[9] and all would have escaped if had not been for the fortuitous arrival of the Coldstream Guards, who nabbed nine conspirators. However, in the darkness and confusion, the remainder of the conspirators escaped.

Cato Street Conspirators and the Police, Courtesy of Wikipedia

Cato Street Conspirators and the Police. Courtesy of Wikipedia.

Among the conspirators that escaped was Thistlewood. The police wanted to capture him and offered a generous reward of one thousand pounds for his apprehension. The reward worked: “He was taken prisoner next morning in his bed.”[10]

Thistlewood, along with five other captured conspirators were sent to the Tower. They were also among the last of the criminals imprisoned there. On the 20th of April, after the jury heard the case, Thistlewood was condemned to death. He, along with four principal accomplices were surrounded by a concourse of spectators booing and hissing and hanged at Old Bailey on 1 May 1820.

The execution was a gristly and ghastly sight. After the bodies had hung for half an hour and were of an “appalling purple hue,” they were cut down. A coffin was placed behind each corpse.

“[The executioner] with the aid of an assistant, lifted the body into the first coffin, laying it on the back, and placing the head over the end of the coffins, so as to bring the neck in contact with the block; the rope and cap were then removed.”[11]

The executioner then advanced and proceeded to severe the head from the body, a deed described as causing spectators to suffer a “shuddering sensation like an electric shock.”[12]

The Cato Street Conspiracy produced a variety of results. It was used by the British government to justify their passage of the Six Acts that suppressed any meetings for the purpose of radical reform. Some people claimed the conspirators had been purposely entrapped to prevent parliamentary reform, and still others completely ignored the incident. As for Cato Street, because the conspiracy was considered so treasonous, the street was renamed Homer Street.

Print from May 1820 showing establishment figures dancing around a maypole (a reference to the date of the conspirators’ execution, May Day 1820). Courtesy of Wikipedia.


  • [1] Chambers, Robert, The Book of Days, Vol. 1, 1881, p. 290.
  • [2] Wilkinson, George Theodore, An Authentic History of the Cato-Street Conspiracy, 1820, p. 6.
  • [3] Chambers, Robert, The Book of Days, Vol. 1, 1881, p. 290. 
  • [4] Ibid.
  • [5] Ibid.
  • [6] Ibid.
  • [7] Wilkinson, George Theodore, An Authentic History of the Cato-Street Conspiracy, 1820, p. 7.
  • [8] Ibid., p. 8.
  • [9] Howitt, William and John Cassell, John Cassell’s Illustrated History of England, Vol. 7, 1863, p. 3.
  • [10] Ibid.
  • [11] Thistlewood, Arthur, The Lives of Thistlewood, Davidson, Brunt, Tidd and Ings, the leaders of the Cato Street Conspiracy, Who were Lately Executed at the Old Bailey, Vol. 5, 1820, p. 40.
  • [12] Howitt, William and John Cassell, p. 3.

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