No-one has definitely spent the whole night in its chambers since Neolithic tribes regularly used it as a shelter with a constant 7C - it'll be a cold damp night for the ten ladies taking part.

Poole's Cavern spokesman Alan Walker said: "It's a really unusual event, in a fabulous venue. We're thrilled to support the Ladies. You never know, they might encounter the ghost of the legendary outlaw Poole himself roaming the chambers!"

The sponsored sleep-over on Friday July 11 will raise funds for two local charities Charis House and Buxton Mountain Rescue.

Buxton Ladies Circle Chairman Susanne Howe said: "We're all really excited about it, but the closer it gets the more nervous we are, we're just not sure what to expect down there."

To cope with the unpleasant sleeping conditions, a "Base Camp" has been provided by the Stockport branch of the camping store Go Outdoors who has also donated £200 which has been matched by Nestle's Buxton Water.

Ladies Circle is an international group for women aged between 21 and 45 with the emphasis on fun, friendship and fundraising and they are always ready to welcome new members.

Anyone who want to make a donation can do so on the fundraising page of www.buxtonladiescircle.moonfruit.com or they can leave donations at the Clarks shoe shop, 17 Spring Gardens, who have kindly agreed to act as a collection point.