Fell Beck is a stream located near the foot of Ingleborough, in the Yorkshire Dales National Park. It is notable for the fact that it runs into Gaping Gill, the second largest natural cave shaft in the UK (after Titan).[1] As it falls down the shaft for 110 metres it is the tallest unbroken waterfall in the UK.[2] It later emerges as Clapham Beck in Beck Head Cave. This was proven by fluorescent dye tests many years ago, but only confirmed by cave divers in the 1983.[2] At times it is blocked off by a temporary dam to allow members of the public to descend the shaft on a winch.[3]