The Royal Windsor Horse Show is facing calls to review its safety procedures after the death of a young female soldier, who was allegedly dragged under a heavy gun carriage.

Lance Bombardier Ciara Sullivan, part of the King's Troop, Royal Horse Artillery, died after falling from her horse following a display witnessed by King Charles and other members of the Royal Family earlier this month.

Each gun and carriage – First World War-era QF [quick firing] 13-pounder field artillery – is pulled at speed by a team of six horses in three rows.

Lance Bombardier Sullivan, known as Sully and described by her commanding officer as a 'fearless and gifted horsewoman', is understood to have been in the back row, closest to the carriage, when the tragedy occurred.

She was wearing the regiment's traditional ceremonial 'busby' hat, part of the King's Troop full dress uniform.

Videos widely circulated online, along with comments posted by friends and relatives of the 24-year-old, have further fuelled claims that she was killed by the gun carriage, which weighs more than a ton, rather than from the initial fall.

The carriage is made of steel and wood with large spoked wheels, and during displays, the riders manoeuvre the heavy artillery through tight turns and arena formations. 

The design dates from an era long before modern safety engineering or protective riding helmets, which critics now say raises serious questions about their continued use in public performances.

One source told The Mail on Sunday: 'Most people assumed at first that she hit her head when she fell, but in the horse world it's no secret that she was run over by the very heavy gun carriage.

'The rider at the front was not able to clearly see the back of the carriage where Ciara was sitting, so could not see that she had fallen and did not know to stop.

'These carriages were invented centuries ago, before modern safety measures. They are not fit for purpose and nor are the hats. There should be a serious review of horse displays like this.'

Another source in the equestrian world added: 'If riders must perform in arenas and in front of crowds then they should be wearing helmets. Not all the horses are used to enclosed arenas and many never seem to get used to loud displays.'

Lance Bombardier Sullivan sustained her injuries as the troop exited the arena at around 7pm on May 15 in Home Park, part of the private grounds around Windsor Castle.

Despite immediate medical treatment at the scene, she could not be saved.

Thames Valley Police told the MoS that her death had been referred to Berkshire Coroner's Office and that it remained 'non-suspicious'.

An equestrian source said: 'It appears she was an accomplished and highly respected rider, disciplined, experienced and devoted to her role within the King's Troop. Yet her loss also raises uncomfortable questions about the dangers inherent in a ceremonial tradition that appears increasingly out of step with modern standards of safety.

'The continued use of traditional headwear that offers only limited protection has to be reviewed in an activity where serious head injuries are an ever-present risk.

'In virtually every other professional equestrian setting, modern protective equipment is considered essential. Yet for reasons of appearance and tradition, ceremonial riders remain exposed to dangers most contemporary organisations would regard as unacceptable.'

Her commanding officer said it was 'this natural courage that made her always the first to volunteer to ride the most demanding of horses'.

Buckingham Palace said the King was 'greatly shocked and saddened' by the tragedy and would privately share his condolences with her family.

The Royal Windsor Horse Show and the MoD declined to comment.