The magistrates had sworn in a very large number of special constables, and had called out the services of a large body of Hussars, a troop of Horse Artillery with two cannons, a regiment of infantry, and nearly eight hundred of the Cheshire Yeomanry and the Manchester Yeomanry. The military forces were all disposed in streets and lanes close to the place of meeting. At the appointed hour, Hunt, the chairman of the meeting, accompanied by a number of his friends and by a band, were seen making their way towards the appointed place. The band played the two popular national airs, "Rule Britannia" and "God save the King"; and it is stated that a large number of those attending the meeting took off their hats in token of respect for the sentiment to which the music gave expression. Mr. Hunt and his friends then mounted the platform, and it was proposed in the most quiet and orderly way that Mr. Hunt should take the chair. The motion was seconded, and carried by acclamation. Hunt thereupon advanced to address the meeting for the purpose of formally opening the proceedings. Miss Martineau's history tells us what happened then. "He had only," says the authoress, "uttered a few sentences when a confused murmur and pressure, beginning at one verge of the field and rapidly rolling onwards, brought him to a pause. The soldiers were upon the people. The magistrates, it appears, had taken it into their heads to issue a warrant for the arrest of the leading promoters of the meeting; the warrant was given into the hands of the local Chief Constable. The Chief Constable declared that he could not possibly attempt to execute the warrant without the assistance of the military; and the magistrates thereupon issued instructions to some of the commanders of the military." Up to this part of the proceedings there seems no contradiction between the account given by the promoters of the meeting and that given by the authorities. The uncertainty is as to how and why the active intervention of the soldiers began. There was, no doubt, confusion of orders and confusion of ideas.

When the Yeomanry were seen advancing, Hunt, who began to be afraid that a panic might break out among those who composed the meeting, called on the people to give three cheers. The Yeomanry possibly mistook the cheers for shouts of defiance, and possibly in some way or another got it into their heads that they were ordered to advance. They did advance, at all events, waving their swords, and apparently with the intention of dispersing the meeting; but of course, as the number of the Yeomanry was comparatively small and the number of the crowd was immense, the only immediate result was that the Yeomanry got thoroughly swallowed up in the crowd and could neither advance nor retreat. Just at this moment, as luck would have it, the two squadrons of Hussars came within sight, and soon reached the verge of the crowd. Thereupon some of the magistrates, who were watching the proceedings, seemed to have thoroughly lost their heads. The impression of some of them certainly was that the Yeomanry were being overwhelmed and trampled down, and they gave to the officer in command of the Hussars the frantic order to disperse the crowd. The trumpet was sounded, and the cavalry charged the multitude. The multitude was in no condition whatever to offer any effective resistance. Even if those who composed the meeting had been prepared or inclined to resist, which they certainly were not, the manner in which they were helplessly packed together would have rendered any sort of resistance impossible. A general stampede set in; the Hussars, it is believed, in general used only the flats of their swords against the people, but as may be easily imagined in such a case, the edge of the sword was sometimes used, both by cavalry and by yeomanry. There is no reason to suppose that the soldiers acted with any deliberate and cruel purpose; but when a collision takes place between a small body of troops and a vast number of civilians whose only resistance is in the mere bulk of their crowd, the soldier striving to make his way onwards is sometimes tempted to use the edge of his weapon in order to clear a passage. In ten minutes from the first movement of the Yeomanry the meeting had broken up in utter confusion; the people had fled this way, that way, and the other; and the field was almost completely deserted, except for the bodies, some dead and some wounded, which still held the ground.

Some pitiful, pathetic evidences of a struggle also remained behind; the ground in several places was strewn with hats, caps, bonnets, coats, shawls, torn skirts, torn petticoats, shoes and slippers, which fugitives had left behind them in the stress and pressure of the flight. The actual deaths were not many, when one considers the density of the crowd and the efforts of the cavalry to clear their way through, although perhaps the very density of the crowd may have been the principal reason why the deaths were not more numerous. Only five or six persons appear to have been killed, and of these one was a special constable, and one belonged to the Manchester Yeomanry, both apparently knocked off their horses and ridden down in the confusion. About thirty wounded persons were carried to the hospitals that day, and about forty more had their wounds looked to and dressed, and were then able to return to their own homes. Others, it is believed, were wounded who did not present themselves at any hospital or infirmary. This is but natural, and is just what occurs on all similar occasions. At every great political gathering a number of men are sure to attend whose hearts are not particularly set on the objects of the popular meeting, and whose first impulse, if there be disturbance, is to endeavour to escape from being identified with any of the proceedings. Such men would be very likely, even if they had received bodily injuries at St. Peter's Field, to make as little noise about the matter as possible. They would betake themselves to their homes privately; would have their hurts seen after in their own houses; and would try to go about their ordinary occupations next day as if nothing had happened in which they had any personal concern. It did not suit many a man in those days to give "some one had blundered" his employer any reason for suspecting that he had been taking a part, however passive and innocent, in the business which ended in the massacre of Peterloo. Looking back now at the whole story of the day's events, it is easy enough to see that the massacre, if massacre it may still be called, was not premeditated on the part of the magistrates or on the part of the troops whom they called in so mistaken a way to their assistance.