Encyclopædia Britannica, Ninth Edition/Thistlewood Conspiracy

THISTLEWOOD CONSPIRACY, or Cato Street Conspiracy, a plot formed in 1820 to murder Lord Castlereagh and other ministers of the British crown, and to seize the Bank and Mansion-House and proclaim a provisional government. Its chief instigator was Arthur Thistlewood, or properly Thistlewaite, born in 1770, the son of a civil engineer in Lincolnshire, who had held a commission in the militia and afterwards in the line in the West Indies. In America and in France he had imbibed revolutionary views, and, having lost his wife's fortune in speculation and on the turf, had planned the desperate scheme probably for his own benefit as well as the good of the nation. The intention was to murder the ministers in the house of the earl of Harrowby in Mansfield Street on the evening of the 23d February. For this purpose between twenty and thirty men assembled in a stable in Cato Street, Edgeware Road, but while they were arming themselves they were pounced upon by the police, and a large number captured, though the majority, including Thistlewood, escaped. A reward of £1000 having been offered for Thistlewood, he was arrested next day at 10 White Street. After a trial Thistlewood and four others were executed on the 1st May, while five were transported. On being asked on the scaffold if he repented, Thistlewood replied, "No, not at all; I shall soon know the last grand secret."

See the Trials of Arthur Thistlewood, James Ings, John Thomas Brunt, Richard Tidd, William Davidson, and others at the Session of the Old Bailey 17–28 April 1820, 2 vols., 1820; and the Gentleman's Magazine for the same year.