The Telegraph has also seen images of a black leopard that was captured and collared on Kenya's Lewa conservancy in the 1990s.

Mr Pilford rejected claims that his paper was misleading about previous sightings, pointing out that it included a photograph of a black leopard taken in 2007 to demonstrate that their findings confirmed previous reports.

He said he had made inquiries about the leopard photographed in the Nation, and was told that it was a captive cat imported from America as a kitten.

He was not aware of the Lewa leopard when he wrote the paper, but said he had since confirmed that the image was genuine.

"I wish I'd know ahead of time about that," he said. "I think you have to differentiate between a sighting and photographic evidence. If someone was to read an article from Kenya that is a the first sighting, I'd understand they'd think that was absurd. The hundred years thing is if you go into the scientific record in written form, there is nothing there, as far as I understand."

"It is still a very rare and unique finding. African leopards have the largest remaining range of any of the sub species. They are photographed very regularly. If melanism was very common thing we'd have seen lots more of it," he said.