Animal cruelty campaigners, who shot to fame with anti-fur adverts featuring naked supermodels, are planning to take on their most ambitious target yet: Britain's 2.6 million anglers.
Fish, insists Peta - People for the Ethical Treatment of Animals - are "complex and intelligent individuals", cleverer than monkeys, who feel pain "like every other animal". So they are preparing posters and lining up celebrities, and models dressed as mermaids, to try to persuade lovers of Britain's most popular sport to end the "terror and suffering".
But the anglers are fighting back, accusing the campaigners of "a lot of hot air" and retorting that fish "simply do not have the brains" to feel pain.
So far, most anti-cruelty campaigners - while vigorously fighting bloodsports such as foxhunting - have given angling a wide berth. Some prominent anglers doubt that Peta will ever have the courage to try publicly to shame so many Britons, headed by such prominent enthusiasts as arch-inquisitors Jeremy Paxman and Chris Tarrant, performers Diana Rigg and Roger Daltrey, and Michelin-starred chef/restaurateur Marco Pierre White.
But the organisation - which has demonstrated against commercial fishing using naked mermaids outside supermarkets - says it is determined to go on to attacking the sport.
Its move comes as BBC2 prepares to launch a new series next month, The Accidental Angler, in which writer Charles Rangeley-Wilson travels the world trying to hook unusual fish.
"Recreational anglers rarely stop to think that fish are smart, interesting animals with their own unique personalities - just like the dogs and cats we share our homes with", says the group in its campaigning literature. "Imagine reaching for an apple on a tree and having your hand suddenly impaled by a metal hook that drags you out of the air and into an atmosphere in which you cannot breathe. That is what fish experience when they are hooked for 'sport'. If anglers treated cats, dogs, cows or pigs the way they treat fish, they would be thrown into prison on charges of cruelty."
They cite a growing number of studies that show that fish create maps of their surroundings, can be trained to perform tasks and can remember how to repeat actions nearly a year later. And they quote Culum Brown, at the University of Canterbury, New Zealand, as saying: "In many areas, such as memory, their cognitive powers match or exceed those of 'higher vertebrates', including non-human primates."
Two-and-a-half years ago the Royal Society published what it called "the first conclusive evidence indicating pain perception in fish", concluding that pain produced "profound behavioural and physiological changes in fish over a prolonged period of time, comparable to those in higher mammals".
The singer Chrissie Hynde said yesterday: "A true sport is one in which each party is a willing participant. I support Peta's campaign because angling is making a bloodbath of our beautiful lakes, rivers and oceans."
Carré Otis, an actress and modelwho poses as a mermaid in the posters, adds: "I was in a sushi bar and it dawned on me - how could I discriminate between a cow and a fish?"
But Marco Pierre White, a keen salmon fisherman, attacked Peta: "They obviously lead very boring lives," he said. "If that's the best they can do, they should get out more."
And Dr Bruno Broughton, the director of the Fishing and Angling Conservation Trust, says the campaign is just "a lot of hot air", adding: "Fish lack the parts of the brain necessary for the registration of pain."
On The Ball: living proof that fish are far from stupid
Albert Einstein is living proof that fish are brainy, say campaigners. A three-year-old goldfish, he has been trained by his owners, computer scientist Dean Pomerleau and his son Kyle, 10, who live near Pittsburgh, to fetch a toy football, shoot it into a goal, and even dance the limbo. "I spend half my life telling people that fish aren't stupid," says Culum Brown, a specialist in fish behaviour at the University of Canterbury, New Zealand.