Inside the Frozen Deep: Mail on Sunday man is first to be pictured in Britain's biggest cave recently discovered below Cheddar Gorge

Journalist David Rose descends hundreds of feet below ground into the Frozen Deep at Cheddar Gorge, Somerset

Explorers smash through boulders to find previously undiscovered chamber

It features country's longest stalactite column which stands at 20ft tall




By the gloomy light of our caving headlamps, it looks like a geological rubbish dump: a brown, muddy chaos of shadowy crevices and boulders – some the size of buses – that fell from the roof. Welcome to The Frozen Deep, the biggest cave chamber in Britain, which has recently been discovered below Cheddar Gorge in Somerset.

By the way, I’m the tiny figure in the middle of the photo standing in the distant white glow at the far wall.

Lit properly for the first time by underground photography specialist Gavin Newman, with five of our team spread out across its vastness holding synchronised flashguns, The Frozen Deep is a wonderland featuring pure white stalactite columns – the 20ft one on the left of the picture is the country’s longest.

Spot me if you can: David Rose's silhouette can be seen at the back of the recently discovered Frozen Deep chamber beneath Somerset's Cheddar Gorge. The white 20ft stalactite on the left is the largest in Britain

Quite a feat: David Rose in the breakthrough dig in Reservoir Hole Cave, Cheddar Gorge, Somerset. Beyond this tight section of passage, explorers found the Frozen Deep Chamber

The Frozen Deep is at the far end of a cave system known as Reservoir Hole. It has been explored by cavers since 1951, but no one had ventured beyond an apparently impenetrable rockfall at the end of its main tunnel, which is called the Grand Gallery.

However, a strong draught blowing from the cracks between the boulders suggested that if a way through could somehow be found, there must be more open cavern.

In early 2008, Dr Pete Glanvill, 61, a retired GP and a doyen of the local caving scene, put a team together to take up the challenge.

Armed with hammers, crowbars, drills, explosives and a large quantity of scaffolding, the team probed various blind alleys in search of the elusive chamber.

Finally they began to push at the right spot. With a series of successive breakthroughs starting earlier this year, they reached the end of a squirm they dubbed Hard Times to became the first humans to enter Resurrection, a massive open rift.

Seen from the side: A graphic shows the journey taken to the Frozen Deep

The Frozen Deep – which could be accessed from a passage 30ft above the floor – was by now just around the corner. That week Glanvill happened to be on holiday. ‘They waited for me to get back before they went down into the chamber,’ he said. ‘I thought that was pretty decent of them.’ It takes a little time to appreciate just how big this chamber is. To get from one end to the other takes close to ten minutes, in part because one has to follow a circuitous route laid between strips of fluorescent tape in order to avoid damaging the unique crystals and cracked mud floors. The floor area is almost 32,291 square feet – big enough to fit in about six of the naves of nearby Wells Cathedral. Measured by volume, The Frozen Deep is almost 1,412 million cubic feet, against the cathedral’s 388,000 cubic feet. Its discovery may not be the end of Reservoir Hole’s secrets. At the lowest part of the chamber, a small stream flows down a muddy passage that the team called Dingley Dell and into a pit, where the roof dips beneath the water’s surface. Vast: Explorers believe the cave could turn out to be even bigger as they think it is linked to other known underground chambers

Preliminary dives have established that the passage continues underwater, and appears to join a much bigger tunnel. At this point, Reservoir Hole is very close to Cheddar’s ‘lost river’ – the massive borehole bearing the River Yeo, a major underground watercourse that emerges at the bottom of the gorge.

In the Nineties, cave divers explored it for more than half a mile, but eventually reached a blockage. ‘The hope now is to get back to the river upstream of that point via Reservoir Hole,’ said team member Martin Grass, 57.

If that happens, perhaps in the next few weeks, it may well be possible to find links with some of the other already-known underground chambers and caves on top of the Mendip Hills, some of them miles away.