Below is the Act passed in 1549 "for the punishment of unlawful assemblies and risings of the King's Subjects" the proclamation of which brought about the phrase "to read the Riot Act". It provided that if, one hour after a proclamation was read out, rioters had not dispersed, they were guilty of High Treason and liable to execution. It also granted immunity from criminal prosecution and civil suit to anyone who, in attempting to disperse or arrest rioters, killed or injured a rioter (these provisions are not reproduced here but similar provisions are contained in the 1714 Act). The Act was regularly re-enacted or continued until the end of the Reign of Queen Elizabeth I.

        This transcription is from Volume 4 of Statutes of the Realm, which was printed in 1819 by Command of His Majesty King George III in pursuance of an Address of the House of Commons, a copy of which is held in the Law Library of the University of Bristol.
 

FORASMUCHE as it ys most necesserie in a Cõmon Wealth to pvyde that tranquilitie and peace maye be contynued in the Realme, and that all thingf beinge contrarie therunto may by foresight be eschewed; Therefore it is ordeyned and enacted by the Kinge our Soveraigne Lorde withe thassent of the Lordes and Cõmons of this psent Parliament assembled and by thauctoritie of the same, that if anye psons, to the nombre of twelve or above, beinge assembled together, at anye tyme after the twelveth daye of Februarye next cõmynge, shall intende goe about practise or put in ure withe force of armes unlaufullye and of their owne auctoritye to murder kill slaye take or ymprisone anye of the Kingf most honorable Privey Counsell, or unlaufully to alter or chaunge anye Lawes made or established for Religion by auctoritie of Parliament, or anye other Lawes or Estatutes of this Realme or anye of them, the same nombre of twelve or above beinge cõmaunded or required by the Sheriff of the Shire, or by anye Justice of Peace of the same Shyre, or by the Mayer Sherifff Justice of Peace or Baylifff of anye Cittye Boroughe or Towne corporate, where anye suche Assembly shalbe unlaufully had or made, by Pclamacon in the Kingf name to retyre and repayre to their owne Houses habytacons or places from whence they came, and they or anye of them notwithstanginge suche Pclamacon, shall remayne or make their abode or contynue together, by the space of one hole hower after suche comaundment or request made by Pclamacon; Or after that, shall willinglie in forcible or ryottous manner attempte to doe or put in ure any the thingf abovespified, that then aswll everie suche abode or contynuynege together, as everie suche acte or offence that after suche Pclamacon comaundment or request had or made shalbe attempted to be done practised or put in ure by any psons beinge of the nombre aforesaide, shalbe judged Highe Treason, in all and singuler those psons that so shall make their abode or contynue together, or shall attempte or cõmytt any suche Acte; and the Offendors therein their aydors abettors and pcurors to be adjuged Traytors to the Kinge and the Realme, and shall suffre execucon of deathe as in case of highe Treason.

[XIV] AND be it further enacted by thauctoritie aforesaide, That the ordre and fourme of the Pclamacons that shalbe made by thauctoritie of this Acte, shalbe as hereafter followeth, or withe the like ordre and wordes in effecte; that ys to saye, the Justice or other pson aucthorised by this Acte to make the saide Pclamacon, shall make or cause to be made an Oyes, and after that shall openlye pnounce or cause to be pnõnced these Wordes or lyke in effecte: The Kinge our Soveraigne Lorde chargeth and cõmaundeth all psons being assembled ymediatly to disperse them selfes and peaciblye to departe to their habitacons or to thire lauful busynes upon the paynes conteyned in the Acte lately made against unlaufull and rebellious assembles: and God save the King.

[XIX] . . . This Acte to contynue untill the ende of the next Parliament.