AN ADVENTURER drowned on a solo cave dive only a short distance from the surface after his breathing apparatus failed him, an inquest heard.

Simon Halliday died at Lancaster Hole, near Kirkby Lonsdale, on January 4, 2020.

Wife Toni told the inquest that the father-of-two had a ‘real zest for life’ and ‘made the most of every minute of every day’.

“Simon was a very loving husband and father,” she said.

“He has left a huge hole in our hearts.”

On the day he died, the 49-year-old travelled down to the dive site with a support team comprising two friends.

Mr Halliday told his team he would be a maximum of three hours.

However, said David McDonough, when the four-hour mark had come and their friend had still not surfaced, he and Kevin Gannon requested help.

Diver Anthony Seddon, who was called out to assist, entered the underwater passage and discovered Mr Halliday, deceased, 14 minutes and 60m in.

Cockermouth Coroner’s Court heard that, when Mr Halliday was pulled out of the water, the oxygen supply pipe from his rebreather appeared to have become disconnected or been ripped out - either during the dive or while the body was being recovered.

Data from the dive computers that Mr Halliday had on him supported the idea that his rebreathing equipment had failed him and he had switched to his bail out facilities.

The exact circumstances that led to the tragedy are unclear.

It was a dive that Mr Halliday had done before, although on January 4 his team noted that there was more water flowing into the passageway than usual.

Mr Halliday did not see this as an issue, but the strength of the current appeared to increase over the time he was in the hole.

The inquest heard that this may have caused him to use more air on his return journey, when he would have been fighting the current.

This problem could have been exacerbated if Mr Halliday had been under stress and breathing more heavily because his air was running out.

The increase in buoyancy as his canisters emptied may have caused him to expend more energy fighting to stay ‘down’ in the passage and avoid drifting towards the roof.

He was also using a rebreather - from Andy Goring at Sump UK - that was in development and was not commercially available.

Rescue diver Jason Mallinson said the equipment used a 'straight fitting' into the rebreather. He said an ‘elbow fitting’, which has a 90-degree bend, would have stopped the fitting unscrewing if that were indeed what happened.

The inquest heard that, after a hiatus, Mr Halliday had taken up cave diving in earnest during a holiday in Egypt around two years before his death.

He was a qualified rescue diver and belonged to various groups, including the Cave Diving Group northern section.

Mr McDonough described Mr Halliday, of Clitheroe, as a person who liked ‘to push himself’ and ‘operate at the extreme’.

He said the dive at Lancaster Hole was not one he himself would have felt confident undertaking.

“That isn’t because I think it’s a dangerous dive,” he said.

“But it is a serious dive.”

Dr Nicholas Shaw, assistant coroner for Cumbria, said it was ‘most likely’ Mr Halliday’s rebreather failed him, leaving him in a race against time. He was not far from the surface when he died.

Dr Shaw recorded a conclusion of misadventure and the medical cause of death as drowning.