Cruelty and squalor of UK puppy farms to be to be exposed in documentary The Dog Factory

The filming reveals dog fighting, over-breeding, and automated feeding systems which starve them of human contact

Dogs are often smuggled into the UK without proper vaccinations, spreading disease in the poor living conditions and leading to the death of many of the animals (Andrew Forsyth/RSPCA)

Disease-ridden puppy farms have been filmed in a documentary which hopes to expose the filthy conditions the animals are forced to live in.

The puppies bred on farms have not previously been investigated to any great extent, due to the puppies being sold in the homes of buyers or in public places.

The Dog Factory, broadcast on BBC1 next Tuesday, follows the dogs from farm to home, finding evidence of dog fighting, cruelty, and other alarming poor practices.

These have included over-breeding, puppies torn from mothers far too young, and automated feeding systems which starve them of human contact.

Experts have said such conditions can have a severe impact on the puppies’ mental health and could make them dangerous and aggressive.

The dogs are often smuggled into the UK without proper vaccinations, spreading disease in the poor living conditions and leading to the death of many of the animals.

In one instance on the documentary a carcass of a calf is left in the same pen as the dogs are kept, and even in licensed farms practices have raised concerns.

Dr John Bradshaw, director of the Anthrozoology Institute at the University of Bristol and author of In Defence of Dogs, said such breeding practices could lead to a rise in aggressive and dangerous dogs.

He said: "My main concern is the way the puppies' brains develop. People take no time to socialise them, they aren’t prepared for going out to live with a family.

"This will make them prone to all kinds of behaviour abnormalities."

A Peta spokesperson said: ‘Most people who buy dogs online or from breeders are unaware of the suffering occurring behind the scenes in this shady business.’