Demonstrations were not at all uncommon in 17th Century England. In fact the term Roundhead was originally coined in response to Students and Apprentices who wore their heir cropped close to the head giving a far more rounded shape to the head in comparison to the norm that of wearing your hair long. The term was used by Royalists as an insult to supporters of Parliament.
Full blown riots were less the norm at the start of the ECW but as the war wore on more and more demonstrations started to turn ugly and Parliament had to struggle between quelling anti Parliament demonstrations and the fear of turning the City against them by not allowing the people to have their say. Lord Essex summed it up best when he famously stated (roughly) "If we beat the King a Dozen Times, He still be King, but he beat us but once and we will be hung as traitors" well words to that effect anyway.
So in an attempt to keep the ECW theme somewhat in the twilight zone I give you a double whammy. First of all the riot that happened on 8th August 1643 (14 days before the first anniversary of the start of the war) was by women. It seems girl power did not start with the Spice Girls! The demonstration was sparked by Parliaments rejection the day before of the latest Peace Proposals. Women with white ribbons in their hats blocked up the approaches to Parliament crying out for peace and down with Pym and Say. The following day they gathered at Palace Yard, but in even greater numbers and presented a petition for peace them banged on the door to Parliament demanding Pym, Say and other Roundheads to be handed over so they could be thrown in the Thames. After an hour the guards tried to clear a passage and when this failed they loaded their muskets with powder and wadding (no bullet) and fired as a warning. The women thinking the guards had no bullet to fire became bolder and violent, tearing up cobbles and other objects carrying them in their skirts and started to pelt the soldiers. After suffering this for some time these troops finally loaded with ball and fired into the crowd. They still seemed to have scruples as the only killed were two men, one of which was egging on the women. Rather than bring the women to submission it emboldened them and more missiles were thrown and chants of "That Dog Pym" were added to the threats and demands. A troop of Wallers Horse arrived but this just aggravated the women more. Shouts of Waller's Dogs were soon followed by the women attacking the troopers. At first these men flayed about them with the flat of their swords but with the women still attempting to drag them off their mounts they started to use the edge. Quickly women started to be injured, some through cuts whilst others by being ridden down. This was enough to start to disperse the crowd but unfortunately not before a women who was passing on an errand was shot and killed. At least one other women died from wounds. The innocent passer by was shot by one of the troopers who was later arrested and charged with murder. Whammy two. His successful defence against the charge of murder? At the range the shot was fired, if he had aimed at the women he would have missed so hitting her had to be an accident!