The prospect would terrify most people: plunging into a series of pitch-black caverns riddled with tight crawlways, underground rivers, vertical shafts up to 150ft deep and numerous ‘sumps’ — long and deep underwater tunnels so murky that, even if you had a powerful light, you couldn’t see a hand in front of your face.
But Chris Jewell and Jason Mallinson were about to do just that in a record-breaking bid to complete the longest-possible journey in underground Britain.
We were standing at the easternmost entrance to the lengthiest caving route in the country through the 54 miles of the Three Counties System, which snakes its way through North Yorkshire, Lancashire and Cumbria.
High on the slopes of Gragareth, a heather-clad fell in the Yorkshire Dales, the vertical opening takes you down to a cave known as Large Pot.
Jason Mallinson (front) and Chris Jewell reach airspace after diving from Ireby Fell Cavern to Notts Pot
Down there, is British caving’s Holy Grail. This extraordinary bid to conquer it was the culmination of almost 100 years of exploration during which new caves were discovered and routes joined together — often by diggers who poured years into clearing blocked passages — to offer the adventurous the nation’s biggest underground journey.
While completing it, the cavers had to swim more than a mile underwater, through seven separate sumps; they had to bend their bodies past the tightest turns, at times inching their way forward in desperately confined spaces on a journey of seven miles and more.
The skill and stamina involved over nearly 20 hours had — until now — been considered beyond even the best in the business.
It is little wonder that Jewell admitted to being ‘a little apprehensive’, adding: ‘If we pull this off, it will be a once-in-a-lifetime trip.’
He smiled . . . then suddenly disappeared down the rope, swallowed up by the Earth. Jewell, 39, an IT consultant from Cheddar in Somerset, and Mallinson, 53, a rope-access technician who lives in Huddersfield, are both veteran cave divers.
The pair were suddenly propelled to worldwide fame three years ago when they played critical roles in the rescue of the 12 boys and their football coach from the flooded Tham Luang cave in Thailand.
On three successive days, both men dived through a mile of underwater tunnels to the chamber where the boys were trapped.
The 13 were carried out one by one, a heroic feat that is the subject of two feature films: The Rescue, a documentary by Oscar-winners Elizabeth Chai Vasarhelyi and Jimmy Chin, due out next month; and Thirteen Lives, a drama version by Apollo 13 director Ron Howard, to be shown next year.
Chris Jewell and Jason Mallinson completed the record-breaking bid of caving the longest-possible journey in underground Britain. The lengthy caving route snakes its way through North Yorkshire, Lancashire and Cumbria
The Thai rescue had the highest-possible stakes. But the sheer difficulty of what the two men were attempting last weekend — starting on Saturday — was far greater.
‘In terms of the caving, this is harder,’ said Mallinson. ‘The dives are longer and deeper, and the water is much colder. And there’s a lot of tiring, dry passage.
‘On the other hand, not having the responsibility of trying to swim while carrying an anaesthetised child does make a difference.’
Until last weekend, no one had seriously thought of doing it in one go. It was too daunting.
When Mallinson and Jewell entered Large Pot, they faced not just those seven miles of caving, of which a mile-and-a-third was underwater. But also the seven sumps, the longest of which had never been dived end to end.
The record attempt required a vast logistical effort to transport diving gear to different spots and stow it along with food, to rig the vertical sections with rope and then, starting on Sunday, to pull the equipment out again.
On Saturday, about 50 cavers were involved in supporting roles — including me. Kevin Gannon, 62 and Secretary of the northern section of the Cave Diving Group, came up with the master plan. A further 20 played their part in preceding weeks.
At the team briefing in a car park in the North Yorkshire village of Ingleton, beforehand, he likened it to an ‘underground K2’, a reference to the pyramid-shaped mountain in the Himalayas that is considered the ultimate challenge for the world’s best mountaineers.
‘But after the months of lockdowns,’ he added, ‘what a great way to bring British cavers together, and to put us back on the world caving map — so long as nothing goes wrong.’
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