It's getting warmer - just look at the frogs

Global warming is already affecting London, the capital's Mayor, Ken Livingstone said yesterday. You can tell by the frogs.

Mr Livingstone, who is amphibian-fancier as much as he is politician, told a conference on how London will be affected by climate change that summers have become warm enough to breed French edible frogs in his garden pond. The Mayor said rising temperatures had allowed them to breed in London for the first time since the Romans.

He treated a City Hall audience of local government officials, economists and scientists to a life history of the frog Rana esculenta. "It was our rarest amphibian for centuries," he said. "I suspect its problem was that unlike our common frog which lays its spawn in February, it wouldn't spawn until the end of May or early June. So with our summers there was never really the time for a generation of edible frogs to make it through in sufficiently large size to get through hibernation." But now global warming had arrived. "People have woken up in terms of their personal experience to the fact that there are the most dramatic changes taking place in climate, certainly within living memory," he said.

The Mayor told the conference about his experience with edible frogs. "I put a few in my garden pond a decade ago," he said. "They are now on their third generation.

"Our summers have become sufficiently warm in London for the first time certainly since Roman times, for edible frogs to establish a base. I shall soon have enough for a dinner party of four. You are welcome to join me."