 Historian Robert Poole has called the Peterloo Massacre one of the defining moments of its age . In its own time , the London and national papers shared the horror felt in the Manchester region , but Peterloo 's immediate effect was to cause the government to crack down on reform , with the passing of what became known as the Six Acts . It also led directly to the foundation of The Manchester Guardian ( now The Guardian ) , but had little other effect on the pace of reform . In a survey conducted by The Guardian in 2006 , Peterloo came second to the Putney Debates as the event from radical British history that most deserved a proper monument or a memorial . Peterloo is commemorated by a plaque close to the site , a replacement for an earlier one that was criticised as being inadequate as it did not reflect the scale of the massacre . 
