"The Cato Street Conspiracy was an attempt to murder all the British cabinet ministers and the Prime Minister Lord Liverpool in 1820. The name comes from the meeting place near Edgware Road in London. The police had an informer; the plotters fell into a police trap.

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When Jamaican-born William Davidson, who had worked for Lord Harrowby, went to find more details about the cabinet dinner, a servant in Lord Harrowby's house told him that his master was not at home. When Davidson told this to Thistlewood, he refused to believe it and demanded that the operation commence at once. John Harrison rented a small house in Cato Street as the base of operations. However, Edwards kept the police fully informed. Some of the other members had suspected Edwards, but Thistlewood had made him his top aide.

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Edwards had presented the idea with the full knowledge of the Home Office, which had also put the advertisement about the supposed dinner in The New Times. When he reported that his would-be-comrades would be ready to follow his suggestion, the Home Office decided to act.

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The British government used the incident to justify the Six Acts that had been passed two months before. However, in the House of Commons Matthew Wood MP accused the government of purposeful entrapment of the conspirators to smear the campaign for parliamentary reform. Although there is evidence that Edwards did incite certain actions of the conspirators, the idea is not supported by modern historians. However, the otherwise pro-government newspaper The Observer ignored the order of the Lord Chief Justice Sir Charles Abbott not to report the trial before the sentencing."

https://en.m.wikipedia.org/wiki/Cato_Street_Conspiracy

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