 The exact number of those killed and injured at Peterloo has never been established with certainty . Sources claim 11 – 15 killed and 400 – 700 injured . The Manchester Relief Committee , a body set up to provide relief for the victims of Peterloo , gave the number of injured as 420 , while Radical sources listed 500 . The true number is difficult to estimate , as many of the wounded hid their injuries for fear of retribution by the authorities . Three of William Marsh 's six children worked in the factory belonging to Captain Hugh Birley of the Manchester Yeomanry , and lost their jobs because their father had attended the meeting . James Lees was admitted to Manchester Infirmary with two severe sabre wounds to the head , but was refused treatment and sent home after refusing to agree with the surgeon 's insistence that " he had had enough of Manchester meetings " . 
