Crowds fled in panic as flames fanned by strong winds moved towards them during the display by the Sealed Knot Society, named after the Royalist secret society, at Witney in Oxfordshire.
Fifty firemen fought the blaze and society members in costume abandoned the reconstruction to help keep the crowds away. Firemen took 30 minutes to extinguish the flames and motoring organisations towed gutted vehicles from the scene and helped to get others started.
Ambulances took spectators suffering minor burns and the effects of smoke inhalation to the John Radcliffe Hospital and the Radcliffe Infirmary Eye Hospital in Oxford. Seventeen spectators were given hospital treatment, as well as three special constables.
Police animal rescue teams also treated several pets in parked cars. The three-day event was due to end today but a police spokesman said later that the society had decided to cancel the final day.
An investigation has begun into the cause of the fire. It is believed to have been started by wadding from a cannon igniting stubble in the 58-acre field in Deer Park Road being used for the re-enactment. It will also examine fire hazards posed by mock battles. Margaret Jephcott, who helped to clear the field after the fire broke out, said: 'It was a very frightening experience. A wall of flames was coming towards us. It was only a matter of seconds and it started to spread. The ground was very dry - I couldn't believe how quickly everything went wrong. It was lucky no one was more seriously injured.'
Her husband, Derek, said: 'It happened incredibly quickly. I saw wadding from one of the guns land and start smouldering and then the field went up. Flames were simply marching towards us.'
Hundreds of families had gathered to see the re-enactment of the Battle of the Windrush Valley, which took place in Oxfordshire in the early 1640s.Reuse content