Multi-millionaire pop legend Sir Paul McCartney has boycotted a number of cancer charities after discovering they carry out tests on animals. The former Beatle vowed to share his fortune with cancer charities after his first wife Linda died from the disease in 1998. But the animal-loving star was shocked to find out organisations that had previously benefitted from his generosity advocate vivisection. MCCartney, a vegan, says, "It became very difficult when Linda died because I said I would support cancer charities. Animal rights groups then wrote to me pointing out that many were heavily into vivisection - and it's true. A doctor we knew out in America just admitted it as a matter of fact, innocently, like 'Well, sure we do.' "What he doesn't realise is that he won't get a donation out of me for that very fact. There are better alternatives but you're not allowed to challenge the status quo."