Lucky, as he was known, ended his days in a south London garden with a harem of female pool frogs imported from Scandinavia.
He had succeeded in breeding in captivity, which means that pool frogs which are at least partly British can be reintroduced into the species' old haunts in the East Anglian fens.
Charles Snell, an amphibian expert at Greenwich University, who looked after Lucky in his garden, said: "Warm winters are not good for hibernating frogs and he kept waking up, which was very bad news. All is not lost, however. I do have pool frogs with British genes in them and I hope a reintroduction programme will go ahead."
Tony Gent, of the Government's wildlife arm English Nature, said: "It's a great shame. All our amphibians - frogs, toads and newts - are having a hard time but it is terrible to have the last known member of a British population go extinct.''
Recent research revealed that East Anglia's remaining pool frogs were very likely to be the remnants of a species that had been living in Britain since the end of the Ice Age. Their population has been devastated by the repeated draining of the Fens.
Three males were found in 1993. Two were released and one, Lucky, was kept by a Norfolk naturalist to see if he could breed with Scandinavian females. Last year he was transferred to the care of Mr Snell, who kept his location secret.
In the meantime no pool frogs have been found in the wild. ``But it is just possible there is still one lurking in a pond somewhere,'' said Mr Gent.
A tiny lizard, less than two inches long, may help to solve the mystery of how quickly early human explorers managed to colonise the remote islands of the Pacific Ocean. Lipinia noctua, a "vagabond" lizard, has been found across the area and is known to stow away on boats.