Shame on Nobu for serving near-extinct bluefin

So when I began to examine why over-fishing has become the number one plague in the world's oceans, I began to look into the activities of Nobu, whose Park Lane restaurant has long been one of the capital's celebrity haunts and where, famously, Boris Becker and a waitress conceived a child in a broom cupboard.

Nobu is one of a number of celebrity chefs who have made a fortune out of selling endangered fish. Is it as bad as those industry captains of old who made fortunes from polluting the seas with chemicals? Maybe it's worse.

Among the chefs serving bluefin tuna when I first wrote a book about the subject, was Gordon Ramsay, who recommended bluefin in his cookery books and sold it in his restaurants. Gordon has since stopped serving bluefin. He has acknowledged the devastation being wreaked on the delicious bluefin by French, Italian and Spanish fleets in the Mediterranean and the Eastern Atlantic. All credit to him for doing so.

Which makes you wonder about Nobu. Why does he go on serving bluefin now WWF warns us that the bluefin tuna population is collapsing and there may be no adult spawning bluefin left by 2011?

Such is the fishing pressure — half of it illegal — that the EU and the misnamed International Commission for Conserving Atlantic Tunas have disgracefully failed to control.

When we came to make a film based on my book, Nobu came up again. I noticed he did not name the fish he was serving at his London restaurants. He referred only, rather guiltily, to Japanese cuts, such as o-toro, without naming the species they were from. But which tuna was it? After five years of "no comment", we pulled off a journalistic first and DNA-tested the tuna in his restaurants.

With the help of Greenpeace, WWF and a lab we know, we compared what our researchers were served with what the waiters said it was. At Nobu Berkeley St, staff told us Nobu didn't stock it. But at Nobu Berkeley St, Nobu London and Ubon, Canary Wharf, all samples tested positive for Atlantic bluefin, caught in the Med.

So we finally got our interview with Nobu — or to be precise with Richie Notar, the New York-based managing partner of Nobu Restaurants who happens to be married to Terry Wogan's niece, Jane.

He promised us faithfully that he would in future put an asterisk by bluefin on the menu saying "environmentally endangered" so people could order an alternative. This he has done at Nobu restaurants in Britain, but he has not done it anywhere else in the world. And he has not taken bluefin off the menu.

Perhaps all the starry accolades have gone to Nobu's head — Kate Winslet calls his food "sex on a plate". Spielberg says: "Your food is the BEST. Just don't tell my mother." Or maybe he takes the same dogged attitude to eating bluefin that many Japanese take to eating whale — that it's a tradition and so it's something they should be allowed to do.

I could respect that. Except that what Nobu is doing is worse than whaling — as practised today. It is participating in the extermination of a species. And when his celeb clientele finally understand that this is wrong, they will turn their backs on his restaurants, never to return. That, I believe, is only a matter of time.

The End of the Line, a film based on the book of the same name by Charles Clover, has its British premiere at 50 cinemas on 8 June. Visit www.endoftheline.com.