The Act declared: Whereas a traitorous and detestable conspiracy has been formed for subverting the existing laws and constitution, and for introducing the system of anarchy and confusion which has so fatally prevailed in France: therefore, for the better preservation of his Majesty's sacred person, and for securing the peace and the laws and liberties of this kingdom; be it enacted...That every person or persons that are or shall be in prison within the kingdom of Great Britain at or upon the day on which this act shall receive his Majesty's royal assent, or after, by warrant of his said Majesty's most honourable privy council, signed by six of the said privy council, for high treason, suspicion of high treason, or treasonable practices, or by warrant, signed by any of his Majesty's secretaries of state, for such causes as aforesaid, may be detained in safe custody, without bail or main-prize, until the first day of February one thousand seven hundred and ninety-five; and that no judge or justice of the peace shall bail or try any such person or persons so committed, without order from his said Majesty's privy council signed by six of the said privy council, till the said first day of February one thousand seven hundred and ninety-five; any law or statute to the contrary notwithstanding...[1]Section 3 of the Act preserved the privilege of Parliament.

Government spies had penetrated the Society for Constitutional Information, and were reporting a surge in its activity and much dangerous talk of a convention rather than parliamentary reform.

The next day another radical, John Thelwall, was arrested and the Prime Minister, William Pitt, appointed a secret committee of the House of Commons to examine the confiscated papers of the London societies.

On 16 May the committee submitted its first report, saying there was a conspiracy and called for the suspension of habeas corpus for eight months.

The bill passed the Commons by 146 votes to 28, after fourteen obstructing divisions by Foxite Whigs.