Can you really be a vegetarian if you eat fish?

The lentils and nut cutlets are starting to fly in a food fight that has pitted vegetarians against those who shun meat but eat fish.

The row follows a report about the problems of finding good vegetarian food in restaurants, which prompted a report in The Independent by our consumer affairs correspondent, who does not eat meat but who does eat fish.

Purist vegetarians have hit back at that article and, in doing so, have rekindled a dispute within non meat-eating circles. The difference, argue the fundamentalist veggies, is clear: eat fish and you cannot be considered a genuine member of the community.

Our finned friends feel pain, they say. Dine on them and your outlook on the animal world is distinctly different to those who stick with mung beans and Quorn. In fact, according to strict vegetarians, those who still eat fish should not even lay claim to the title. They must only refer to themselves as "pescatarians".

One reader wrote yesterday: "One of the reasons we vegetarians get such a poor service is that there are idiots out there, such as Martin Hickman, who claim to be vegetarian and then go on to explain that they eat fish."

The Vegetarian Society, which has recently launched a fish welfare campaign, said: "Vegetarians don't eat fish and they never have. Many things have changed since The Vegetarian Society was founded in 1847, but two important definitions haven't: 'Vegetarian' someone who doesn't eat animals. 'Fish' cold-blooded, water-dwelling animal. Fish may not appear as cute and cuddly as young lambs. However, they do feel pain and they do suffer."

Kelly Slade, a campaigns officer for Animal Aid, said: "The best scientific evidence demonstrates that fish are capable of feeling pain and stress like any other animal. When they are hauled up from the deep, the intense internal pressure can rupture their swimbladders, pop out their eyes and push their insides out through their mouths. They die from crushing, suffocation or from being sliced open on the decks of a ship."

Peter Stevenson, the chief policy adviser at Compassion in World Farming, said that there was little doubt among scientists that fish were capable of suffering. "It's widely accepted by scientists that fish do feel pain," he said. "I don't think there's any doubt about that. If you're serious about being a vegetarian, you don't eat fish."

Despite this, Mr Stevenson added that beginning a vegetarian lifestyle by first cutting out meat, and continuing to eat fish, was quite a good way of making the transition. "When I became a vegetarian I carried on eating fish for the first year, and I think many people find it easier to make the change gradually; I wouldn't knock someone who started off by just cutting out land animals."

But Professor James Rose, of the University of Wyoming, argued recently that fish "do not possess the necessary and specific regions of the brain, the neocortex, to enable them to feel pain".

But aside from the question of whether fish suffer, the health benefits of a pescatarian diet are manifold. According to The Sea Fish Industry Authority, a diet rich in fish and low in red meat can improve circulation, lower the risk of heart disease and cancer, and improve sex drive.