A “mixture” of factors may have combined to trigger the fatal collapse of a young soldier on an Army test march, an inquest has heard.

Corporal Joshua Hoole, described as “fit, capable and determined”, died within an hour of collapsing on a hot day during an annual fitness test (AFT) at Brecon, Wales, on the morning of July 19 2016.

Cpl Hoole, of Ecclefechan near Lockerbie, Dumfries and Galloway, died three years after three Army reservists suffered fatal heat illness during an SAS selection march in the Brecon Beacons.

Corporal Josh Hoole funeral
The coffin of Cpl Hoole is carried into Crichton Memorial Church in Dumfries by colleagues and his brother Tyrone (right) (Andrew Milligan/PA)

An inquest into Cpl Hoole’s death has already heard soldiers were aware it was to be “the hottest day of the year” and the march start time had been brought forward, due to the weather.

Of the 41 corporals and lance corporals taking part in the AFT that day, 18 pulled out, collapsed or withdrew – a rate of 42%.

The inquest, being held at Birmingham Coroner’s Court, has previously heard the average drop-out rate on the same route for the whole of the previous year had been 3%.

Cpl Hoole, 26, collapsed at 8.52am just 400m from the end of the “eight-miler” loaded march.

Earlier in the route, two other soldiers had suffered suspected heat injuries, but the march had continued.

Corporal George Knight had “blanked out” into a hedge, while Corporal Anasa Matau was found with his “eyes rolling back in his head”.

On Thursday, Army cardiologist Major Andrew Cox told senior coroner Louise Hunt he did not believe that heat should be recorded as a factor in Cpl Hoole’s official cause of death.

Philip Hoole
Cpl Hoole’s father Philip Hoole is representing the family at the inquest (Jacob King/PA)

He said: “I believe this was a sudden arrhythmic death syndrome (SAD) death.”

He suggested that “exertion” could have been a contributing factor.

Philip Hoole, Cpl Hoole’s father and himself a former Army sergeant major who had helped run similar exercises, is representing himself and the family at the inquest.

Having taken part in AFTs in the heat, he said: “I used to call it cooking yourself from the inside out.”

He asked Maj Cox about Cpl Hoole’s symptoms, which included “hyperventilation”, “agitation” and being seen “staggering” at one stage.

But Maj Cox replied: “There was still no evidence he was at a very high temperature.”

He added: “I am not convinced it was heat-related and although I accept there are some symptoms, I don’t put them down to heat.”

Mr Hoole said: “I don’t actually believe it’s one thing, it’s a mixture of things.”

He added it was his view that the heat, a lack of acclimatisation and adrenaline were all key factors.

Mr Hoole also pointed to a “trend” between those who had pulled out or collapsed – including Cpl Hoole – coming from the north of England and Scotland, where the weather had been cooler.

The inquest heard Cpl Hoole’s collapse, when it came, was sudden, with witnesses describing him straighten up and complain of cramp, before falling sideways.

Despite evidence of almost immediate CPR being carried out by Army medics and a defibrillator being put in place, he could not be revived.

The inquest continues.