On the 12th of May, Mr. Henry Dundas brought down on behalf of the government, a second message from the King, importing that seditious practices had been carried on by certain societies in London, in correspondence with other societies; that they had lately been pursued with increasing activity and boldness, and had been avowedly directed to the assembling of a pretended National Convention, in contempt and defiance of the authority of Parliament, on principles subversive of the existing laws and the constitution, and tending to introduce that system of anarchy prevailing in France; that his Majesty had given orders for seizing the books and papers of those societies, which were to be laid before the House, to whom it was recommended to pursue measures necessary to counteract their pernicious tendency. A large collection of books and papers was, in consequence, brought down to the House; and, after an address had been voted, a resolution was agreed to, that those papers should be referred to a committee of secrecy. A few days after the King's message was delivered, the following persons were committed to the Tower on a charge of high treason: Mr. Thomas Hardy, a shoemaker in Piccadilly, who officiated as secretary to the London Corresponding Society; Mr. Daniel Adams, secretary to the Society for Constitutional Information; Mr. John Home Tooke; Mr. Stewart Kyd; Mr. Jeremiah Joyce, preceptor to Lord Mahon, eldest son of the Earl of Stanhope; and Mr. John Thelwall, who had for some time delivered lectures on political subjects in London.
Under the influence of excitement resulting from the Government statement of the discovery of a plot to assassinate the King, and which plot never existed outside the brains of the Government spies, a Special Commission of Oyer and Terminer was issued on the 10th of September, 1794, for the trial of the State prisoners confined in the Tower on a charge of high treason. On the 2d of October, the Commission was opened at the Sessions House, by Lord Chief Justice Eyre, in an elaborate charge to the grand jury. Bills were then found against all who had been taken up in May, except Daniel Adams. Hardy was first put on his trial at the Old Bailey. The trial commenced on the 28th of October, and continued with short adjournments until the 5th of November. Mr. Erskine was counsel for Hardy, and employed his great talents and brilliant eloquence with the most complete success. After consulting together for three hours, the jury, who, though the avowed friends of the then administration, were men of impartiality, intelligence, and of highly respectable characters, returned a verdict of Not Guilty. There has seldom been a verdict given in a British court of justice which afforded more general satisfaction. It is doubtful whether there has been a verdict more important in its consequences to the liberties of the English people. On the 17th of November, John Horne Tooke was put on his trial. The Duke of Richmond, Earl Camden, Mr. Pitt, and Mr. Beaufoy, were subpoenaed by the prisoner; and the examination of William Pitt by Mr. Tooke and his counsel formed the most important feature in the trial, as the evidence of the Prime Minister tended to prove that, from the year 1780 to 1782, he himself had been actively engaged with Mr. Tooke and many others in measures of agitation to procure a Parliamentary reform, although he now not only deemed the attempt dangerous and improper, but sought to condemn it as treasonable, or at least as seditious. Mr. Erskine, who was counsel for Mr. Tooke also, in a most eloquent and powerful manner contended that the conduct of his client was directed only to the same object as that previously sought by Pitt himself, and that the measures resorted to, so far from being criminal, were perfectly constitutional. Mr. Pitt was extremely guarded in his replies, and professed very little recollection of what passed at the meetings which he attended. A letter he had written to Mr. Tooke at that time on the subject was handed to him, which he pretended he could scarcely recognize, and which the judge would not permit to be read. Mr. Sheridan, who was likewise engaged in the agitation for political reform, and subpoenaed by Mr. Tooke, gave unqualified evidence in favor of Mr. Tooke respecting the proceedings at those meetings. The trial continued till the Saturday following, when the jury were out of court only six minutes, and returned a verdict of Not Guilty!