A wave of “Frankenstein dogs” that are unable to live healthy, natural lives are being created by unlicensed “canine fertility clinics”, a report has said.

People with no training or qualifications are illegally giving prescription medicines and performing artificial insemination on dogs, according to research by Naturewatch Foundation, an animal welfare charity.

Its investigation found more than 120 such clinics in the UK, which claim to offer veterinary services but often are run by people with no training. It describes these facilities as “laboratories” creating Frankenstein puppies that “are destined to suffer for their looks”.

French bulldogs most at risk

Breeds of particular concern include French bulldogs, a brachycephalic (or flat-faced) breed that is beset with severe health problems. An estimated four-fifths of puppies are born by caesarean as they have been bred to have narrow hips and large heads, which make natural births dangerous.

They also struggle to breathe because of their flat-faced nature, which shortens their airways, and often requires surgery to fix.

Now new types of these dogs are being bred which have even worse health outcomes, vets have warned. Although naturally short-haired, “mutated” fluffy or hairless versions of French bulldogs are being bred by irresponsible breeders.

“The genetics are so mutated, they will have issues,” said Aoibheann Canavan, a vet who has practised in Derby and Dublin.

She explained that the struggles of ordinary short-haired Frenchies to breathe mean that they find it difficult to pant to regulate their temperature, so fluffy versions are at an even greater risk.

“They overheat on hot days with no nose, so now the fluffy ones will die even faster,” she said. “That fluffy dog will die in two minutes [on a hot day]. It can’t go anywhere.”

Dogs mutated for ‘novelty value’

Justine Shotton, the president of the British Veterinary Association, said: “We think [the problem is] increasing because of the demand of pandemic puppies and how much money these dogs are being sold for. These ‘novelty’ puppies are bred just because they can be popular and novel online. That’s completely wrong and not in the best interests of welfare.

“Always speak to your vet before you decide to breed your dog or get a puppy. They can tell you if it’s right for your dog to be breeding or not.”