Watson was tried first and the hearing took over a week . The chief prosecution witness was Castle , who had been on the organising committee for both meetings . Hunt appeared as a defence witness and accused Castle of trying to make him commit treasonable acts on at least two occasions . Defence counsel exposed previous instances where Castle had entrapped others into committing crimes and , without naming him as a spy , presented him to the jury an agent provocateur . The jury accepted the defence 's case and Watson was found Not Guilty . No further evidence was presented against the other defendants and they were also acquitted . The riots marked the start of a period of mass anti-government meetings , marches and riots , including the march of the Blanketeers ( March 1817 ) , the Pentrich rising ( June 1817 ) and the Peterloo Massacre ( August 1819 ) and only ending after the failure of the Cato Street Conspiracy ( February 1820 )
Peterloo Massacre
Peterloo Massacre
Spa Fields riots