Climbing quickly became a huge part of Craig’s life and before long, he’d set his sights on one of mountaineering’s biggest prizes – the Seven Summits. “We were going to do the highest mountain on each of the seven continents within seven years. That was the original plan. Thinking of the ‘Seven in Seven’ in those days was a big thing,” he explains.

He made a good start, successfully summiting Mont Blanc and Kilimanjaro, but two years and two mountains into the mission, Craig’s goal was cruelly snatched away from him. “It was a stress injury. I’d torn the cartilage from my rib cage, and it just meant that you couldn’t do anything too extreme that would cause that kind of exertion.” He was, he says, absolutely gutted. Climbing was what he lived for. “It was just what we did,” he explains. But although the injury was a blow, the time off left him with space to explore a new passion.

“[They’re] completely, completely different, but so similar. Both of those are environments that are incredibly challenging. [You need] the right gear and the right training [and] it’s about the challenge against yourself and against the elements.”

Not only did they tick similar boxes for Craig, he also found they involved surprisingly similar skills. Organisation – having a plan and sticking to it – is key: “With mountaineering, you’ve got all the struggle and the strain to get to the top, to summit, and you’re not on there very long before you have to start considering the elements and the dangers of coming back down again, which is often harder than going up.

“With both sports, accurate timekeeping is also essential – it can often be a matter of life or death.”

“And scuba diving is exactly the same. You do all that preparation and you go and you do the dive. You get down to the bottom and you’re only actually there a couple of minutes before you have to start considering the element of coming back up, which takes a lot longer than going down.”

With both sports, accurate timekeeping is also essential. “When you’re underwater you need to know the depth and time you’re at. And over-running by a couple of minutes on some dives at different levels can be life-changing. So it is incredibly important to know what time it is.”

On the mountain it’s the same. As Craig says: “If the sun gets too high and the face becomes more challenging you’ve increased your risk.” And if you miss your summit time and fail to turn back early enough, you can end up climbing in the dark, or worse.

Craig remembers one incident in particular: “We were on the west face of the Eiger and we had a storm roll in. There were hundred mile an hour icy winds with sleet and it took us an awful lot longer to come down than we’d anticipated. That was quite a challenge. We were descending in the dark for some of it. We weren’t meant to be!”

As with his narrow brush with death while diving, it was a combination of logical thinking, problem solving but most of all, years of training which got Craig down in one piece. If there’s one thing that Craig has learned from his years in dangerous environments, it’s that experience and knowledge is key. “There’s never a problem that can’t be thought out, he says. “That’s the mindset that you’ve got to have both on a mountain and underwater. You need the equipment to help you manage the situation [but it’s knowing] how you apply it, and that’s down to your experience.”

There are very few people who can claim to have climbed some of the planet’s most serious mountains and also dived to extreme depths beneath the oceans. Craig Mainprize – who has climbed to 5,895 metres above sea-level and dived 54 metres below it – has done both. He’s not only lived to tell the tale, but relished the adventures along the way. The main reason for that? Whether it’s mountaineering or diving, he has completely mastered his craft.