A Hump is a hill of any height in Britain or the Isle of Man that has a drop of at least 100 metres on all sides. There were 2982 Humps at the end of July 2018.
The list of Humps was first published by Mark Jackson in the book More Relative Hills of Britain, tabulated by David Stone and available via Lulu.com from 2010. As well as doing significant original research, Mark drew on the work of several people including Alan Dawson, Eric Yeaman, Clem Clements, Rob Woodall, Bernie Hughes and Pete Ridges, as acknowledged in the book.
All Marilyns have over 150m drop and so are by definition Humps, but almost half the Humps are not Marilyns. More information about Humps is available in these sources:
On 29 July 2018, Rob Woodall and Alan Whatley became the first people to climb all the Humps, when they reached the top of the most difficult Hump, the Old Man of Hoy. A month earlier they had climbed Lianamuil, a difficult sea stack off the west coast of Mingulay, having earlier nearby climbed Arnamuil, another tricky stack.