Julian Lennon resurfaced at the Cannes film festival looking about as happy as one of the harpooned whales he is trying to save. He swore off interviews eight years ago, in the wake of a family bust-up when he criticised Yoko Ono, his father John’s widow. But a surprise decision by the Japanese government to resume whaling has made him blow his top.

“I am devastated,” he declares. “If we witness the slaughter of the humpback whale, it will outrage the planet. Apart from standing in front of the harpoon, being on show is the only thing I can do to express my feelings.”

Lennon, 44, has been living what he calls the life of a “nomad” in recent years. He has a home in Italy and travels around the Mediterranean, concentrating on art, photography and music. He hasn’t made an album since 1998, but is releasing one later this year about “the problems we face, environmentally and otherwise”.

He has also produced a remarkable film, The Gathering: Return of the Whale Dreamers. He had been content to let his old friend, the director Kim Kindersley, promote the 86-minute documentary along La Croisette to distributors. The film painstakingly links the splendour of whales to the uncanny understanding of them by ancient civilisations around the world. But, as Kindersley admitted, the subject matter failed to inspire the money men and he was struggling to sell. Enter Lennon, on the penultimate day of the festival. Suddenly, buyers were queuing on the beach to talk, pay homage and reach for their chequebooks.

“My thought,” says Lennon, who financed most of the film, “is that, whether it is the music, the family legacy, Dad’s legacy or simply the name itself, then at least use it in the right direction.” The protection of whales, he says, could not be a more fitting campaign.

“Killing whales is not a long-standing tradition in Japanese culture,” he states. “They only began to hunt and eat whales during the blockade of Japan in the second world war. It is not necessary. But now the humpback whale population has risen from 300 to 6,000 since a campaign of protection began in 1975, the Japanese government thinks it’s okay to start killing again. Even 70% of the Japanese people don’t want to kill whales.”

Lennon, with longish dark hair pushed back from a high forehead, an earring in his left ear and a cigarette held not far from his lips, strikes a similar campaigning stance to his father. The only thing missing is the Liverpool accent. He attacks his subject with the same mixture of controlled anger, puzzlement and wry scorn that Lennon Sr showed towards warring politicians. “I have to say, though, that it was my mum, Cynthia, who made me the conscious man I am today,” he says.

“Obviously, Dad had his beliefs and his way of doing things. But it was Mum who taught me my values in life. It is out of respect for her that I want to be a good son, a good man and a good human being.”

The Gathering: Return of the Whale Dreamers will be released later this year

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