Gaping Gill

The surrounding rock is Great Scar Limestone, laid down in a warm tropical sea around 350 million years ago and containing corals, brachiopods and crinoids. Mildly acidic water draining off the peat has been widening joints and bedding planes here for a very long time, which is how a system this large and complex formed.

• The unfenced shaft mouth and the beck pouring into it, viewed from the surface. This is the normal destination for ordinary visitors.
• A wide grassy hollow on open fell, well above the valley, on the flanks of Ingleborough.
• The chamber itself only on a public winch meet, or as an experienced caver with proper skills and equipment.

• Sturdy boots, waterproofs and warm layers. Fell weather changes fast and the chamber is cool and draughty.
• Food and water for the round trip.
• Map and compass or GPS. Cloud can come down on Ingleborough quickly.
• A torch if you have a booked descent.

• The entrance is unfenced. Keep well back from the lip, keep children close and control dogs.
• Wet rock and steep ground around the shaft are genuinely dangerous.
• On busy meet days, queues for the winch can be long, so the descent may involve a lot of waiting on exposed ground.
• The chamber is cold and wet, and a soaking is part of the experience rather than a mishap.
• Outside organised meets there is no visitor route underground. Independent caving here demands specialist experience and equipment.
• If you cannot manage a long, rough uphill walk, this one will not work for you.

John Birkbeck tried to descend in 1842 and got as far as the ledge that still carries his name, roughly 55m down. Edouard Martel made the first descent to the floor in 1895, and caving clubs later developed the winch descents that still bring visitors down today.