London’s Cato Street Conspirators Plot Assassinations Summary

  • Last updated on November 10, 2022

The Cato Street Conspiracy was the climactic event in the conflict between the forces of reaction and reform that emerged in England during the years after the defeat of Napoleon I in 1815. Twenty conspirators plotted to assassinate the political leadership of England, but the plot was discovered and thwarted. Parliament enacted the repressive Six Acts, which increased governmental powers against sedition, after the scope of the conspiracy was revealed.

Summary of Event

After the collapse of Napoleon I’s French armies at Waterloo and the finalization of the treaties that emerged at the Congress of Vienna in 1815, England looked forward to a period of peace and a return to normalcy. The generation of war, however, caused extensive changes in England’s economy and in the nation’s political attitudes. Almost one-half million British troops were demobilized without support and found themselves in a society that already had high unemployment and a low standard of living. During the years immediately following the war, the government of the prime minister, the second earl of Liverpool, failed to recognize the extent of the domestic problems and the expectations of the people. Liverpool and most of his ministers were hostile to the Enlightenment ideas that demanded social change; British leadership was interested in returning to pre-war conditions—the Great Britain and the Europe of the ancien régime France;ancien régime —and looked upon change and reform as revolutionary and related to the disastrous French experiment of the previous generation. Cato Street Conspiracy (1820) London;Cato Street Conspiracy Liverpool, second earl of [p]Liverpool, second earl of;and Cato Street conspiracy[Cato Street conspiracy] [kw]London’s Cato Street Conspirators Plot Assassinations (Feb. 23, 1820) [kw]Cato Street Conspirators Plot Assassinations, London’s (Feb. 23, 1820) [kw]Street Conspirators Plot Assassinations, London’s Cato (Feb. 23, 1820) [kw]Conspirators Plot Assassinations, London’s Cato Street (Feb. 23, 1820) [kw]Plot Assassinations, London’s Cato Street Conspirators (Feb. 23, 1820) [kw]Assassinations, London’s Cato Street Conspirators Plot (Feb. 23, 1820) Cato Street Conspiracy (1820) London;Cato Street Conspiracy Liverpool, second earl of [p]Liverpool, second earl of;and Cato Street conspiracy[Cato Street conspiracy] [g]Great Britain;Feb. 23, 1820: London’s Cato Street Conspirators Plot Assassinations[1100] [c]Terrorism and political assassination;Feb. 23, 1820: London’s Cato Street Conspirators Plot Assassinations[1100] [c]Laws, acts, and legal history;Feb. 23, 1820: London’s Cato Street Conspirators Plot Assassinations[1100] [c]Wars, uprisings, and civil unrest;Feb. 23, 1820: London’s Cato Street Conspirators Plot Assassinations[1100] Thistlewood, Arthur Cobbett, William Hunt, Henry More, Hannah

During the war years, there were indications that forces of change and reform were emerging in Britain. On the political right were the Luddites, Luddites who appeared in 1812, constituting a secret, anti-industrial sect that supported the values of labor among craftsmen, particularly the making of textile Textile industry;and Luddites[Luddites] s. Textile industry;English Luddites despised and feared the machine age and the disappearance of their livelihoods. On the political left were reformers such as Robert Owen Owen, Robert , a factory owner and utopian socialist, who argued in publications such as New View of Society: A New View of Society (1813) that capitalist owners had an obligation to assume responsibility for the well-being of their workers and their families.

Liverpool’s government was not sympathetic to any of these calls for reform. By mid-1815, Britain was in an economic depression, a situation aggravated by passage of the protectionist Corn Law Corn Laws of 1815, which forbade the importation of foreign grain until that grain reached the so-called “famine price” of eighty shillings per quarter. Supporters of the Corn Law argued that the law would provide support for British agriculture, which had lost most of its foreign markets after the peace in Europe. Suffering high unemployment and shouldering the effects of the Corn Law, the general populace could not afford the increased price, leading to widespread hunger in Britain during 1815-1816.

The situation was further aggravated in 1816 when Parliament eliminated the 10 percent income tax that had been enacted to support the costs of the war with France; most of this tax burden fell on those with high incomes. Concurrently, Parliament enacted new duties on many articles. This “sales tax” led to higher prices, harming the general populace, which was not prepared or able to pay the tax. Organized opposition to these measures and conditions began in 1816. William Cobbett, Cobbett, William who had a national following based on his Political Register Political Register , was an advocate for radical political, economic, and social reform. Along with other radicals, such as Henry Hunt Hunt, Henry , Cobbett believed that the fundamental structure of government needed changing, so that it would reflect the people’s needs and aspirations.

On December 2, 1816, Spa Fields Riot (1816) a group of radicals gathered a crowd at Spa Fields, north of London, to discuss political change. Exchanges between the crowd and police resulted in violence and several arrests. Hannah More More, Hannah , a contemporary feminist reformer and writer, later argued that no gains would be achieved by “breaking of windows, or breaking of laws.” As a result of the Spa Fields Riot, Cobbett’s Cobbett, William activities were restricted. He migrated to the United States in 1817 but returned to England in 1819. Hunt Hunt, Henry scheduled a public address at St. Peter’s Field in Manchester Manchester, England for August 16, 1819, to call for reforms in government and society. A struggle broke out between police and a few in the crowd, leading police to an unwarranted cavalry charge into the crowd. Scores of people were wounded and eleven died in what is called the Peterloo Peterloo Massacre (1819) Massacre of 1819. Liverpool’s government immediately suspended the writ of habeas corpus Habeas corpus;in Great Britain[Great Britain] and restricted meetings and activities it believed were seditious.

The crisis between the old order and its challenger had reached a new level of intensity. In an effort to curtail the spread of radicalism and violence in December, 1819, the Liverpool government presented the repressive Six Acts. These acts required quick trials on charges of misdemeanors, registration of all newspapers, a new newspaper tax, new powers of search and seizure for the government, prohibition of training in firearm use, and restrictions on public meetings. All these measures were clear violations of traditional English freedoms.

The government’s policies and actions inflamed the radical militants, who, with twenty men under the leadership of Arthur Thistlewood, Thistlewood, Arthur entered into a secret plot to assassinate the entire British cabinet during a dinner meeting at the home of the earl of Harrowby in Grosvenor Square, London, on February 23, 1820. Through informants, police learned of the plot and, as the conspirators were leaving a building on Cato Street, they arrested many of those involved; the next day several others were arrested. In the sensational trial that followed, five of the conspirators, including Thistlewood, were sentenced to death, and the others received extensive prison sentences. The Cato Street Conspiracy failed, the reformers were discredited, and the Six Acts Six Acts of 1819 were enacted.


The Cato Street Conspiracy demonstrated the extent of the political polarization that developed during the five postwar years in Britain. In its aftermath the repressive Six Acts became law, significantly restricting traditional freedoms. These measures reflected the sentiments of those—the landowners and aristocrats—who associated calls for reform with revolution. They feared that weakness in dealing with the reformers would result in a revolution in Britain comparable to the French Revolution (1789) French Revolution (1789);and Great Britain[Great Britain] .

A younger generation of leaders—Robert Peel, Earl Grey, and others—recognized the need for some reforms in order to address dangerous economic, political, and social conditions and to unite the country; they did not fear change and adopted a more progressive approach to governing. Although assassination attempts were directed at British leaders during the nineteenth century, a plan as ambitious as the failed Cato Street Conspiracy would not surface again in Britain until the mid-twentieth century.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Anand, Vidya, and Francis A. Ridley. The Cato Street Conspiracy. London: Medusa Press, 1977. An adequate introduction to the forces that resulted in the conspiracy and the crisis of Regency England.
  • citation-type="booksimple"

    xlink:type="simple">Chandler, James K. England in 1819: The Politics of Literary Culture and the Case of Romantic Historicism. Chicago: University of Chicago Press, 1998. An important scholarly work that places the conspiracy within the context of the literature of dissent and reform.
  • citation-type="booksimple"

    xlink:type="simple">Gash, Norman. Lord Liverpool: The Life and Political Career of Robert Banks Jenkinson, Second Earl of Liverpool, 1770-1828. Cambridge, Mass.: Harvard University Press, 1985. Still the best biography of Liverpool. Includes an excellent chapter on his government postwar policies that contributed to the conspiracy.
  • citation-type="booksimple"

    xlink:type="simple">Plowright, John. Regency England: The Age of Lord Liverpool. New York: Routledge, 1996. An excellent study of British politics during the early nineteenth century. Plowright provides a well-written and provocative section on the 1815 to 1820 period that culminated in the conspiracy and the Six Acts.
  • citation-type="booksimple"

    xlink:type="simple">Reid, Robert. The Peterloo Massacre. London: William Heinemann, 1989. An excellent account of the massacre in Manchester, the suppression of the protesters, and the subsequent trials that contributed to the origins of the conspiracy.
  • citation-type="booksimple"

    xlink:type="simple">Shelley, Percy Bysshe. The Mask of Anarchy. New York: Woodstock Books, 1990. Written in 1819 as The Masque of Anarchy by the contemporary English poet, in remembrance of the massacre in Manchester. Reprint of the 1832 edition.
  • citation-type="booksimple"

    xlink:type="simple">Stanhope, John. The Cato Street Conspiracy. London: Jonathan Cape, 1962. An excellent authoritative study of the Cato Street Conspiracy that is balanced, based on the effective use of primary sources, and well written.
  • citation-type="booksimple"

    xlink:type="simple">Wilkinson, George Theodore. An Authentic History of the Cato Street Conspiracy: With the Trials at Large of the Conspirators, for High Treason and Murder. New York: Arno Press, 1972. Based on extensive use of primary sources, this history of the conspiracy is valuable even with its sensational statements and implications. Originally published in 1820.

Cobbett Founds the Political Register

Luddites Destroy Industrial Machines

Congress of Vienna

Battle of Waterloo

Second Peace of Paris

British Parliament Passes the Six Acts

British Parliament Passes the Reform Act of 1832

Related Articles in <i>Great Lives from History: The Nineteenth Century, 1801-1900</i>

Thomas Carlyle; William Cobbett; George IV; Second Earl of Liverpool; Robert Owen; Sir Robert Peel; Percy Bysshe Shelley. Cato Street Conspiracy (1820) London;Cato Street Conspiracy Liverpool, second earl of [p]Liverpool, second earl of;and Cato Street conspiracy[Cato Street conspiracy]

Categories: History