Arthur Thistlewood had led the group of Spencean Philanthropists, revolutionary followers of Thomas Spence who advocated common ownership of land and the 'rights of man'. It was not Thistlewood's or the Spenceans' first brush with high treason. They had planned another revolution four years earlier, when speaker Henry Hunt was to incite a riot which would turn into armed insurrection. At the first meeting, the crowd chose to present a petition to the Prince Regent instead; the second did end in the Spa Fields riots, but the planned takeover of the Tower of London and Bank of England failed. Evidence against Thistlewood and others given by a police spy was discredited, and the case against him collapsed. However, the causes of discontent increased in the following years. The economic hardships and unemployment which had followed the end of the Napoleonic Wars continued. Fearful of civil unrest, the state responded brutally to protest. In 1819, eighteen peaceful protestors were killed by cavalry in the Peterloo Massacre. Immediately afterwards, the government passed the Six Acts which aimed to suppress protest meetings and publications. Thistlewood was convinced by his travels to France and the United States - who had experienced their own recent revolutions - that revolution was the only answer. He was imprisoned for twelve months in 1817 after challenging the Home Secretary Lord Sidmouth to a duel, but resumed his radical activities following his release.
William Davidson was the mixed-race son of the Jamaican Attorney-General and a local woman. He had trained as a lawyer in Scotland, but left the profession and was later impressed into the Navy. He then studied maths, worked as a cabinet-maker in Birmingham, and finally moved to London. In the aftermath of the Peterloo Massacre, the former Methodist Sunday School teacher lost his faith and became involved in radical politics. At his trial, he suggested that he might have been mistaken for another man of colour, something which had happened to him before. He also reportedly told the jury, 'you may suppose that because I am a man of color I am without any understanding or feeling and would act the brute; I am not one of that sort'. The trial judge claimed in response, 'you may rest most perfectly assured that with respect to the color of your countenance, no prejudice either has or will exist in any part of this Court against you; a man of color is entitled to British justice as much as the fairest British subject'. Davidson also asked the court:
Would you not rather govern a country of spirited men, than cowards? I can die but once in this world, and the only regret left is, that I have a large family of small children, and when I think of that, it unmans me.A newspaper report describes Davidson as going to his death 'with a firm step, calm deportment, and undismayed countenance ... his conduct altogether was equally free from the appearance of terror'.
James Ings had been a butcher in Portsea, Hampshire before running a radical coffee shop in Whitechapel. After the business failed, he lived in lodgings apart from his family and committed to violent protest, apparently stating he wanted to cut off the heads of Lord Sidmouth and Lord Castlereagh. When George Edwards, Thistlewood's second in command, showed the Cato Street plotters a newspaper announcement of a government dinner, Ings offered to be first into the house to kill the Cabinet. In fact, the item had been planted by the authorities working with Edwards, who was a government agent: no such dinner was taking place. The conspirators' plans made under Edwards' encouragement formed the basis of their arrest and conviction. While awaiting execution, Edwards wrote to his wife, 'I must die according to the law, and leave you in a land full of corruption, where justice and liberty have taken their flight from, to other distant shores.'
Former shoemaker Richard Tidd shared Ings' desire to kill Castlereagh and Sidmouth in revenge for Peterloo. Like Thistlewood, he was a veteran of the Spa Fields riots - as was another shoemaker, John Brunt, who had also been impoverished by the economic depression. Brunt spelled out the reasons he and others had turned to radical politics: 'I had, by my industry, been able to earn about £3 or £4 a week, and while this was the case, I never meddled with politics; but when I found my income reduced to 10s a week, I began to look around.' According to contemporary reports, Brunt 'suffered extremely' during his execution: a reminder of the brutality of the conspirators' punishment. The court had ordered that after their death, their heads were to be cut off and their bodies quartered, in an echo of the punishment for treason in earlier ages. In the event, that part of the sentence was 'omitted'.
