A huge underground chamber, thought to be the largest discovered in the South West for 60 years, has been revealed below Cheddar Gorge by a group of six cave divers.
The massive space, which has been named "The Frozen Deep" by the team, is estimated to measure around 60 metres in diameter and up to 30 metres in height.
It contains some of the most stunning calcite formations ever found under the Mendips, including two five-metre-tall pure white columns of calcite surrounded by pure white flowstone covering the walls and floor.
The epic discovery was made by the "Tuesday Diggers", a group of local experienced cavers which includes a retired teacher, two retired GPs and Nick Chipchase who recently celebrated his 65th birthday.
Cheddar Gorge and Caves director, Hugh Cornwell, said: "This is a truly significant discovery by the 'Diggers' which opens up a fascinating new chapter in the history of Mendip cave exploration.
"The question already emerging is whether they can now find a connection from The Frozen Deep to the River Cave. For the moment, however, cavers across Mendip will celebrate the courage, endurance and spectacular achievements of the Diggers.
"They will now consolidate their find by taping out walkways to protect the calcite formations from damage and carry out laser surveys of all the chambers, before allowing a limited number of cavers under their supervision to visit The Frozen Deep," he added.
The Diggers have been given exclusive access by Longleat, which owns Cheddar Gorge, for the past four years to dig in "Reservoir Hole" which is 150 metres east of the famous Pinnacles in Cheddar Gorge.
They concentrated on a side passage of the main cave and eventually broke through to a 20m long rift, then removed a large slab to crawl a further 15m into another chamber, 25m high and 20m long, which they named "Resurrection Chamber".
This led them to a loose boulder slope, which ended in a 12m vertical pitch. Returning last Tuesday with rope and tackle, they descended the pitch into the largest chamber yet discovered under the Mendip Hills, containing the most stunning calcite formations to be found in recent times in any Mendip cave.
The "Tuesday Diggers" are: Martin Grass, Alison Moody, Dr Pete Glanvill, Dr Tony Boycott, Nigel Cox and Nick Chipchase.
The caves are formed by the action of water wearing away limestone as it seeps through the rocks.
The phenomenon has made Mendip a national centre for caving. One famous cave, Swildon Hole, is six miles long. Some caves have been found to contain tonnes of prehistoric animal bones, while one, Aveline's Hole in Burrington Combe, has been identified as the earliest scientifically dated human cemetery, with remains up to 10,400 years old.