What sad creature perpetrated that? I thought.

And then I realised that I actually knew who was behind it, because I'd met her. That was back in the '80s, in the USA, in a field near the little town of Higgins, Pennsylvania. She was an Englishwoman named Ingrid Newkirk and she was leading a PETA demo against a bunch of the local rednecks who had organised a pigeon shoot. Not the sort in which you try to down a wood pigeon rocketing out of the treetops: these pigeons were the city kind, trapped, boxed and trucked to the field, then released, blinking, into the sunshine. Some of them actually got off the ground before they were shot. Others didn't even make it that far.

The whole thing was indefensible and it was plain to me that PETA was in the right. And so I told Ingrid when we met. She was blonde, of indeterminate age with her English accent only slightly eroded and she was passionate in the PETA cause. Eventually, the talk turned to fishing. I told her that, like most anglers these days, I practised catch-and-release, that I even used barbless hooks.

"Oh, thank you! Thank you!" she cried.

"So fishing's OK with PETA then?" I said.

"Oh, no," said Ingrid, "You're next."

But back to that crudely-executed picture of a dog hooked in the jaw - it's supposed to make you think that a fish feels pain in the same way as a warm-blooded, complex mammal. It's by no means new - it's been displayed all over the USA for months, I was told by Dawn Carr, a New Yorker who has been shipped into the UK by PETA to organise an anti-angling campaign here. "It's been a fantastic success in the US" she told me, "particularly the billboard campaign of the hooked dog. Each time we've featured the dog, the response has gone through the roof!". She wasn't able, however, to give me any hard numbers. Meantime British anglers can look forward to demos at fishing matches, she told me, featuring Gill the Fish: A six foot tall, shiny blue fish mascot "I'll be taking him with me" she said, "along the river bank. We'll talk to the anglers, try to get them to realise the suffering to the fish. We'll get a debate going."

The sort of debate Ms Carr will enjoy with, let's say, members of the Melchester AA fishing a critical match on the Witham, or what might happen to Gill the Fish, doesn't bear thinking about. Following the official PETA line, she'll probably point out that "more and more people are choosing alternatives to fishing and eating fish. Hiking, wildlife watching, and a vegetarian diet are among the many choices that are better for us, the animals, and the environment. Eating fish, meantime, is dangerous. Like the flesh of other animals, fish flesh contains excessive amounts of protein, fat, and cholesterol. Fish (and shellfish) can accumulate extremely high levels of toxins , which can cause health problems ranging from kidney damage and impaired mental development to cancer and even death. Leafy, green vegetables are much better for you."

If she and Gill are still on dry land after this, she may come to the seriously gritty part of her anti-fishing message as summed up on the PETA website. "While fish cannot always express pain and suffering in ways that humans can easily recognise, common sense tells us that fish feel pain," it declares. "Fish may not be cute and cuddly but they feel pain in very much the same way." And who says so? Why, Dr Donald Broom, of St Catherine's College Cambridge. "The pain system in fish is virtually the same as in birds and mammals," she quotes him as saying.

Trouble is, that, when you look into it, Dr Broom's academic speciality turns out to be the welfare of farm animals. He is not an ichthyologist, a fish scientist. None of his studies, listed in Who's Who, bear any relation to fish. Furthermore, when approached, he refuses to be interviewed.

Newkirk, inarguably is a charismatic leader, but with, some might think, a penchant for somewhat naive self-revelation. This, for example, is how she describes her conversion to Veganism.: "I bought live snails in an Italian market and was driving home with them in a brown paper bag when I suddenly got the feeling I was being watched! I looked over and they had pushed the bag open and were sitting on the edge of the bag, looking over with those little horns they have, figuring out how to get down. And I thought, "Oh, good lord," and released them in my garden.

When I read this in an American magazine, it took me straight back to my own encounter with Newkirk at that demo in Pennsylvania. After she'd declared that fishing was next on the list for the attentions of PETA, she told me of how she'd decided that the sport must go. She'd gone fishing herself, she said. Just the once. "I caught an eel,. And getting the hook out killed it. But just before it left for another planet, it looked at me with its beautiful little eyes and said "Please help me".

An hour or two later, I saw Ingrid being carted off by four burly Pennsylvania state cops, which didn't prevent her from waving and smiling at me. Soon after that, the demo broke up in farce. The crafty rednecks had ambushed the truck bringing a Port-a-Loo to the PETA demonstrators. Deprived of this and believing, possibly, that it would be unethical to use the hedge, they dispersed. It was, I remember thinking, an appropriately zany ending to the day.

Not zany, though, as in funny. There is something ominously screwball about PETA's leadership and more than a faint whiff of the totalitarian, the new Puritanism. Which makes it really ironic that PETA is targeting angling. Because Izaak Walton, the sport's icon, when he wasn't fishing, was heavily into the politics of his time - on the anti-Puritan side. Old Izaak would have known what to do with PETA.