Following the Peterloo massacre of August 16, 1819, the UK government acted to prevent any future disturbances by the introduction of new legislation, the so-called Six Acts which labelled any meeting for radical reform as "an overt act of treasonable conspiracy".

Parliament had reconvened on November 23 and the new acts were intorduced by the Home Secretary Lord Sidmouth. By December 30 the legislation was passed, despite the opposition of the Whigs. The acts were aimed at gagging radical newspapers, preventing large meetings, and reducing what the government saw as the possibility of armed insurrection.

The acts were:

• The Training Prevention Act made any person attending a meeting for the purpose of receiving training or drill in weapons liable to arrest and transportation. More simply stated, military training of any sort was to be conducted only by municipal bodies and above.
• The Seizure of Arms Act gave local magistrates the powers to search any private property for weapons and seize them and arrest the owners.
• The Seditious Meetings Prevention Act required the permission of a sheriff or magistrate in order to convene any public meeting of more than 50 people if the subject of that meeting was concerned with "church or state" matters. Additional people could not attend such meetings unless they were inhabitants of the parish.
• The Blasphemous and Seditious Libels Act toughened the existing laws to provide for more punitive sentences for the authors of such writings. The maximum sentence was increased to fourteen years transportation.
• The Misdemeanours Act attempted to increase the speed of the administration of justice by reducing the opportunities for bail and allowing for speedier court processing.
• The Newspaper and Stamp Duties Act extended and increased taxes to cover those publications which had escaped duty by publishing opinion and not news. Publishers also were required to post a bond for their behaviour.

See also: police state