Country: British carp are under threat. Big fish being smuggled into th e country are bringing with them fatal diseases

They may be dedicated to snaring their victims on barbed hooks, but carp anglers have an unlikely passion for fish welfare. Anyone seen handling a carp awkwardly is severely reprimanded. Killing carp is taboo.

Jim Parry watched in despair as all the carp in the small lake he owns in Suffolk died. It was like witnessing old friends being decimated. "Every day I went to the lake there would be more of them dead," he says. "It was heartbreaking. Some of these fish were 40 years old and I had caught them quite a few times. There was a lot of memories lying dead at the bottom of the lake."

Jim's stock was wiped out after he introduced five new carp into the lake. They weighed between 20lb and 28lb each, costing around pounds 5,000. They also carried a deadly parasite. By the time they and the other 75 carp already living in the water were dead, Jim reckons at least pounds 20,000 worth of fish were lost.

Jim was almost certainly a victim of an unlikely trade in illegal foreign carp. "They were definitely from abroad, probably Eastern Europe," he says. "I was naive and believed everything the dealer told me, but he was totally unscrupulous. I know he's wiped out God knows how many other fisheries and he's still trading." It will be another two years before Jim's lake can be fished again.

Carp smuggling may sound harmless, even comic, but some experts say it will wipe out Britain's native population of the species. As with rabies, and foot-and-mouth disease, Britain has remained in splendid isolation from diseases endemic among fish on the continent. But the relaxation of European Union border controls in 1993 and carp anglers' obsession for ever bigger fish have conspired to end this.

With a huge body, a tiny head and an ever-open mouth, carp wouldn't win a piscine beauty pageant. But they are loved by Britain's 50,000 carp anglers for being the biggest coarse fish and for being wily, hard fighters. Carp angling exploded in the 1980s and carp anglers are notorious for being fanatical, spending huge amounts of time and money on the sport.

Once caught, the carp is weighed, photographed and returned to be caught again. Fish become well known, some even being named, and regularly live to be 60 years old.

The impetus to smuggle carp comes largely from lake owners, who charge anglers high prices if they can deliver big fish. Given the demand, these are just not available on the domestic market. Ian Marks of the Specimen Anglers Conservation Group says the problem is a simple matter of greed: "There's a short supply of large carp and a lot of people who want to catch them. Anglers will pay around pounds 400 a year to fish on a lake where there will be large fish. The wallet rules thinking."

Carp weighing around 20lb are worth pounds 500, while those over 301b could fetch pounds 2,000. In the warmer, bigger waters of Holland, France and Eastern Europe these are commonplace. The official British record of 551b 4oz is regularly bettered.

However, European waters are awash with disease. The most serious threat comes from Spring Viraemia of Carp (SVC). This attacks fishes' gills and their immune system, leaving them open other ailments. Most imported European fish are immune carriers of SVC, but British carp with no resistance are nearly always wiped out on contact.

Unheard of apart from isolated cases, Britain has seen around 30 outbreaks in each of the past two years, with many more thought to be covered up. Massive death tolls are feared this spring when the disease strikes carp weakened by spawning. Ian Marks believes British carp will not survive the epidemic: "It's terrible, we're on the verge of a large scale disaster. It will kill off nearly all the indigenous fish, leaving just the foreign ones resistant to SVC."

The Ministry of Agriculture, Fisheries and Food (MAFF) appointed an investigator at Christmas with the sole responsibility to identify and prosecute smugglers. Among the carping community the identity of illegal importers is an open secret. Yet proving who they are is almost impossible unless they are caught red handed.

Tony Dallas and his son Mark, who trade as Premier Fish Supplies in Billericay, Essex, are the only dealers to have been prosecuted for smuggling fish in the past few years. Others have been convicted of falsifying stocking certificates.

Last May they were fined a total of pounds 5,250 by magistrates at Dover for twice illegally importing over 20,000 carp, tench, roach and bream from France. This came after customs officers, prompted by MAFF, mounted an operation to monitor the pair's movements through British ports.

Tony insists the effects of SVC are exaggerated and that the labyrinth of rules surrounding the import of fish is unnecessary and confusing. "We got caught out and learnt our lesson," he claims. "Other dealers make accusations about me because I am good at finding stock, so they say I'm up to something. People say I'm the Mr Big. I wish I was." The pair's latest scheme is to introduce starlets, a variety of sturgeon, into British waters. These can grow even bigger than carp.

A fisheries officer at the National Rivers Association says the dealers are highly organised: "They work together, buying from each other and swapping health certifications. To be honest we don't know about most of what goes on. The importers are making huge amounts of money."

Seasoned carp anglers are also opposed to the introduction of foreign stocks on aesthetic grounds. Tim Paisley, editor of the specialist magazine Carp Talk, prefers to fish for home grown carp: "Its hard to explain, but a lot of anglers want to catch fish that have grown and matured in their lake, even if they are a bit smaller. It's just tradition." The carp world, he says, is divided: "A lot of anglers just want big fish. They have one-track minds and they don't care where they come from or what the consequences are. For others the idea of catching a 50 pounder that has just come off a boat is sacrilegious."