An inquest into the death of Beki Hellens has heard that she suffered a catastrophic injury that was not survivable.

Beki, of Tithe Road, Chatteris, died on July 26, 2015 when she was involved in a jet ski collision at the South Lakes Ski School in Little Paxton.

The 22-year-old, who was a competent and experienced jet skier, was riding a custom-built orange Superjet stand-up jet ski and had only been out on the lake for about 20 seconds when the incident occurred, just after 11am.

The other jet ski was being ridden by Nicholas Rudd, aged 43, who had never ridden a jet ski before, and had received instruction that morning from Beki's fiancé, Paul Turner.

The jury at Peterborough Town Hall heard that a 999 call was received at 11.13am and the first of two ambulances arrived at 11.28am, after being redirected from another call.

Emergency crews from Magpas and the East of England Ambulance Service's hazardous area response team also attended the scene.

By the time the paramedics from the first ambulance arrived, Beki was on the shore and a bystander was performing CPR as Beki had gone into cardiac arrest.

Paramedic Martin Henley told the inquest that details of the incident relayed by the bystanders were sketchy, but initially the crew suspected Beki had suffered a head injury.

"One of her pupils was misshapen and there was a small mark above her right eye," he said.

Mr Henley went on to explain how Mr Rudd was visibly upset and shaken and kept repeating 'what have I done?' and 'I think I may have killed her'.

Assistant coroner Simon Milburn told Mr Henley that, according to the expert medical evidence, the "catastrophic injury" had caused a transection of Beki's aorta and her injury was "unsurvivable".

He also told the paramedic after he had concluded his evidence: "The evidence suggests there was nothing you could have done".

Beki continued to receive emergency care at the scene and then a decision was made to transfer her by land ambulance to the trauma unit at Bedford Hospital. Shortly after arriving, the emergency medical team decided to cease CPR and she was declared dead at 12.48pm.

The inquest continues.