Buffett

He said he had been inspired to give away money by investor Warren Buffett and other philanthropists.

Many investors have come to appreciate the relative stability offered by a commodity once dismissed by the billionaire Warren Buffett as "lifeless" and "neither of much use nor procreative".

On its website, African Parks lists a number of high-profile donors including the European Union, Rob Walton, heir to the Walmart fortune, and Howard Buffett, son of Warren Buffet.

Mr Gates said he has been inspired to give away money by investor Warren Buffett and other philanthropists, however critics of his foundation say Mr Gates uses its charitable status to avoid tax and that it has undue influence over the global health system.

Warren Buffett has announced he will retire as chief executive of Berkshire Hathaway at the end of the year.