1940 The “Blasted Hole” in Simpsons Pot was enlarged and the connection was made with the bottom of Swinsto. Hull Pot was explored after the construction of a dam to divert water away from the side passage. The BSA lease on “Cragdale” came to an end. Seven youths became lost in the Alderley Edge Mines and the search to find them took 24 hours. The first volume of the Journal of the Mendip Exploration Society was published, in 1947 this was renamed British Caver.
1941 The first serious cave accident on Mendip occurred down GB Cave when a caver fell 10ft and landed on his head. The entrance to Mossdale was discovered and Bob Leakey free-dived through several short sumps during his often solo explorations.
1942 J Coleman & NV Dunnington finished their survey of Pollnagollum after two years, at 3.5 miles it was the longest cave in Ireland. Quaking Pot was explored from the first pitch to the chamber at the bottom of the third pitch where it was decided that further exploration would need explosives.
1943 The first exploration of Grange Rigg included digging through a boulder choke to reach the final chambers. The BEC were the first club in Britain to use Electron Ladder, on the 12m pot in Swildons.
1944 The UBSS dug into Rod’s Pot and Sidcot School Speleological Society dug into Longwood Swallet. In January a naked Bob Leakey solo free dived the then sump in Disappointment Pot and dug out beyond it, to convert it into a duck with 1 inch of airspace. Over the next few months the cave was pushed until it joined Hensler’s Streamway.
1945 FG Balcombe dived in Alum Pot sump, Goyden Pot and Keld Head. In Derbyshire a survey of Speedwell Mine was started.
1946 The entrance shaft leading into Lancaster Hole was discovered. Notts Pot was discovered and explored down to the sump. The CRO was reformed after the war. The Northern Pennine Club (NPC) and Red Rose Cave & Pothole Clubs (RRCPC) were formed. The South Wales Caving Club(SWCC) was formed and dug out the bottom entrance to Ogof Ffynnon Ddu (OFD). The first dives were made in the OFD resurgence. The Cave Research Group (CRG) and Cave Diving Group (CDG) were formed.
1947 The first edition of Pennine Underground was published as was the first volume of BSA Cave Science. The CPC found the remains of a body in Gaping Gill and police investigators were lowered into the Main Chamber using the CPC winch. Iron ladders were fitted to the main shaft in Lancaster Hole to help with access. The BSA took out a lease on the land to control access to Lancaster Hole. Cornes Cavern (Lancaster/Easegill) was first entered; the largest cave passage discovered in England at that time. Oxford Pot was dug out in Easegill Beck and explored as far as Spout Hall. On Mendip Sump I in Stoke Lane Slocker was passed by free-diving and Wookey 9 was reached by FG Balcombe and D Coase. The WCC dug into Cuckoo Cleeves and UBSS opened up August Hole.
1948 The Upper Wharfedale Fell Rescue Organisation (UWFRA) was formed. Cow Pot was connected into Lancaster Hole by the NPC. Car Pot was bottomed and surveyed by CPC after a dig. The first Transactions of the Cave Research Group were published. The UBSS made their first trip to Co Clare and surveyed in Poulnagollum.
1949 Stream Passage Pot was connected to the GG system. The Bar Pot entrance was dug out and connected to GG. Ireby Fell Cavern was discovered. Penyghent Pot was discovered by the NPC. The Buxton Water Sump was passed in Peak Cavern by divers, the Muddy Ducks were passed by the sherpas on the same day and this gave a dry route into the major extensions; the two parties met at Surprise Pitch. The original short entrance series of Agen Allwedd was pushed and the main cave was discovered.