Crufts: Dogfight at the Kennel Club

It was the documentary that shocked animal lovers and lifted the lid on the cruel breeding techniques and widespread genetic illnesses which blight the world of pedigree dogs. But now the leaders of the attempt to stamp out potentially-fatal inbreeding practices. highlighted in a controversial Panorama exposé. claim they have fallen victim to a vicious backlash from diehard traditionalists who refuse to yield to scientific evidence.

The Independent has spoken to those in the vanguard of the reform movement against the historic Kennel Club system of breeding. They claim they have been targeted by anonymous internet smear campaigns in which they and their families have been accused of being animal rights extremists and left feeling like "terrorists".

The producer of the controversial film, Pedigree Dogs Exposed, said she had been accused of withholding medication from a dog so it could be filmed having an epileptic fit.

Meanwhile, one campaigner who highlighted the agonising genetic problem syringomyelia, which renders the skulls of spaniels too small for their brains, was accused of having Münchausen's syndrome by proxy – the psychological condition in which sufferers induce symptoms in others to draw attention to themselves.

Another pensioner, with decades of breeding experience, claimed she was subjected to threats and abuse for speaking out about scientific concerns.

The depth of anger following the broadcast of the Panorama special in August has shone the spotlight on a deep and widening rift in the dog world. It comes as the BBC, which has been televising the event since 1966, is facing mounting pressure to decide whether it will show next year's Crufts championship and yet another major animal charity, the PDSA, last week joined the RSPCA and major commercial sponsors – including dog food makers Pedigree – in pulling out of the March event.

On one side of the dispute are those who claim breeding practices which condemn pedigree animals to short and painful lives in return for meeting unacceptable aesthetic standards are rife. On the other are those who insist the problem affects only a tiny fraction of the UK's 23,000 top show dogs.

Beverley Cuddy, editor of the pet lovers' bible Dogs Today, who has organised a petition on the Downing Street website calling for legislation to control breeding techniques, said both she and her late parents had been targets of anonymous web postings by disgruntled breeders claiming she is a troublemaker with a grudge against her former employers at the Kennel Club – allegations she vehemently denies.

"I have to say there are not many other professions that would get you this much abuse," she said "It is like I am some sort of extreme terrorist. It is like a war. People behave very badly when they feel threatened. Some people in the show world are so afraid of reform they are shooting the messenger. They are snapping before they think about it," she said.

So poisonous is the current atmosphere that many dissidents are too frightened to speak out, she claimed. "Whistleblowers are treated more seriously than those who breed dogs with serious health problems. It is a curious world where the people who speak up are treated as the world's worst, while the people doing things wrong are protected."

The internationally-acclaimed filmmaker Jemima Harrison spent two years making the documentary with her company Passionate Productions. The film is the subject of an Ofcom complaint filed by the Kennel Club, who say that the film was unfairly edited. She said she had been the victim of a "whispering campaign" as well as being plagued by angry letters and emails. Ms Harrison was inspired to make the documentary following the death of her pedigree flat-coated retriever. "I have been accused of being a signed-up member of Peta and of being bitter and twisted because I lost three dogs to cancer. You are accused of being an animal rights activist if they don't like what you are saying," she said.

She believes it is time the BBC, which has appointed an independent panel to advise it on the scale and tone of future coverage in light of the revelations made in the documentary, acted decisively. "I would be disappointed if they don't drop Crufts. There is room for dog shows but an awful lot has to change for them to be a healthy and positive thing for dogs. It is still too early. In many cases these will be the same dogs trotting around the ring that were there when we filmed."

Crufts, now fronted by Ben Fogle, remains hugely popular with viewers, attracting audiences of 14 million. But there is growing disquiet over the prospect of license payers' money being used to televise what RSPCA chief vet Mark Evans described as a "parade of mutants". Critics believe BBC bosses are faced with a "Miss World Moment" – the point in the 1980s when the politically-incorrect beauty pageant was shunted to the edges of national life by being dropped from prime time schedules.

But many remain deeply affected by what they saw in the documentary – which was criticised by the Kennel Club and some breeders as being unfair and one-sided.

One of the examples depicted the 2003 Best In Show winner Ch Yakee a Dangerous Liaison, known to his friends as Dave the Peke, having to be cooled down on an ice pack to prevent him overheating during the award ceremony. It was also claimed in the run up to the show the dog had undergone an operation to help it breathe.

Margaret Carter, an expert in cavalier spaniels, has described how after appearing in the documentary she had been advised to go to the police after a breeder had allegedly threatened to punch her. The 65-year-old said she too received threatening and abusive emails accusing her of wanting to "ruin" the breed, which is prone to syringomyelia.

"The cavaliers are an endangered species because of their lack of genetic diversity, but the big breeders are in denial so they took it out on the messenger," she said.

Last month, the Kennel Club, which has set breeding standards and run Crufts for more than 100 years, announced what it described as the "most significant shift in assuring the health and welfare of dogs in the UK", in the form of a new strategy. This, it said, would ensure that no dog is bred for features that might prevent it seeing, walking and breathing freely. A spokeswoman for the Club condemned personal attacks on reformers. "Nobody should be picked out individually and targeted in that way. We have to be more responsible than that. Emotions are running high at the moment," she said.

However, Ms Harrison remained sceptical over the prospect of change. "I will believe it the day I receive a bunch of flowers and an invitation to Clarges Street [Kennel Club HQ] to discuss our findings and what can be done to improve dogs' health," she said.