A pug gasps for breath, his face so flat he damages his eyes if he bumps into things; a cavalier King Charles spaniel writhes in agony and must be put to sleep to end its pain; a distraught owner holds his beloved boxer who is fitting uncontrollably...
Two years in the making, Pedigree Dogs Exposed (Tuesday 19 August 2008, 9pm, BBC One) lifts the lid on the true extent of health and welfare problems in pedigree dogs in the UK.
Seventy-five per cent of the seven million dogs in the UK are pedigrees, and they cost their owners over £10m in vet fees every week.
This in-depth investigation suggests they are in serious trouble, plagued by genetic disease due to decades of inbreeding.
They are also suffering acute problems because of the showring's emphasis on looks over and above function and health.
Some physical traits required by the Kennel Club's breed standards have inherent health problems (short faces, wrinkling, screw-tails, dwarfism) while other problems occur because of exaggerations bred into dogs by breeders trying to win rosettes.
Deliberate mating of dogs that are close relatives is common practice and the Kennel Club continues to register dogs bred from mother-to-son and brother-to-sister matings.
Scientists at Imperial College, London, recently found that pugs in the UK are so inbred that, although there are 10,000 of them, it is the equivalent of just 50 distinct individuals – making them more genetically compromised than the giant panda.
Steve Jones, Professor of Genetics, UCL, says: "People are carrying out breeding which would be, first of all, be entirely illegal in humans and secondly is absolutely insane from the point of view of the health of the animals."
He adds: "In some breeds they are paying a terrible, terrible price in genetic disease."
The film exposes the devastating consequences of such genetic disease for dogs and the distress it causes their owners.
Disturbing footage is shown of a cavalier King Charles spaniel writhing in agony due to syringomyelia, estimated to affect up to a third of the breed.
They have been bred with skulls too small for their brains, explains veterinary neurologist Clare Rusbridge: "The cavalier's brain is like a size 10 foot that has been shoved into a size six shoe – it doesn't fit."
Boxers suffer from several life-threatening health issues – including heart disease and a very high rate of cancer, especially brain tumours.
There are no official figures to say how many boxers suffer from epilepsy but in some breeds it is 20 times the rate found in humans. Two-year-old Zak is filmed while fitting and the distress the disease causes for him and his owners is obvious.
The film also demonstrates how some breeders produce dogs with pronounced physical attributes – "exaggerations" – in their efforts to attract a dog show judge's eye.
The breed standards are set by the Kennel Club but are open to interpretation and the film shows how, as fashion changes, so do the dogs, leading to serious health and welfare problems in some breeds.
Bulldogs, for example, have been bred to be such an unnatural shape that most can no longer mate or give birth unassisted.
The RSPCA's Chief Vet Mark Evans says: "The show world is about an obsession, about beauty, and there is a ridiculous concept that that is how we should judge dogs…
"It takes no account of your temperament, your fitness for purpose potentially as a pet animal – and that to me just makes absolutely no sense at all."
The film also exposes famous show champions that continue to father puppies despite having serious inherited disease, and demonstrates that some breeders cull perfectly healthy puppies on purely cosmetic grounds.
As the filmmaker Jemima becomes increasingly concerned with what she uncovers, she challenges the Kennel Club.
The Kennel Club, however, robustly defends its position as the guardian of dog health, pointing out the initiatives it has taken to improve pedigree dog health – including their accredited breeder scheme which sets a code of conduct for breeders and asks them to make use of health screening schemes.
It also insists that "the vast majority of dog breeds are healthy".
Ultimately, the film concludes that far from enough is being done.
As Professor Jones says: "If the dog breeders insist on going further down that road, I can say with confidence really that there is a universe of suffering waiting for many of these breeds – and many if not most of these breeds will not survive.
"They will get so inbred that they will be unable to reproduce and their genes will come to a dead end."