Yet there were times when he felt his life had been futile, and the mood of despondency that had sometimes come upon him in his most active years - which, following Samuel Johnson, Churchill called the "black dog" - seems to have been with him in much of his later life.

BBC: A Point of View: Churchill, chance and the 'black dog'

The Black Death and the Transformation of the West, by David Herlihy, edited by Samuel Cohn.

ECONOMIST: Millennium issue

More recently he had been attempting, along with African climbing guide friend Samuel Kinsonga, to break the record for the fastest ascent of Kilimanjaro, as part of their anti-racism Black and White Makes Sense Campaign.

BBC: Irish climber Ian McKeever killed on Mount Kilimanjaro