Hidden behind a red-bricked cottage on a rural Cambridgeshire lane lies one of Britain's most hidden and shameful secrets. Anybody would be forgiven for not batting an eyelid at this farm, but the suffering going on behind its gates has been going on for decades.

Welcome to Harlan Interfauna – Britain's last commercial breeders of beagles for experimentation. Within industrial units, hundreds of dogs await a fate worse than death inside laboratories across the world.

For over thirty years this business has got away with murder, factory farming dogs for a life of misery and suffering. During this time those involved have been exposed many times - each investigation revealing animal cruelty, dogs fearful of human contact, filthy conditions and staff incompetence.

• Harlan Interfauna's workers kill hundreds of puppies and former-breeders each year with their bare hands, simply because they are deemed as unprofitable.
• Dogs on site will only ever see sunlight when they are loaded into a van and carted to a laboratory. Only 20 minutes exercise, compromising of a run in a corridor, is provided each week according to a Sunday Times investigation in 2011.
• Beagles are provided with only a small scoopful of sawdust for comfort. They are confined in concrete pens with little stimulation for days on end. Photographs from inside the beagle units show faeces covered floors and filthy conditions.
• In 2011, a former employee of Harlan Interfauna spoke out against what they had witnessed. Senior staff punched and kicked dogs, others shaved obscene language into their furs and wrote on their faces with marker pens. Filthy conditions are shown in photographs and videos, with dogs cowering through fear of human contact and others biting on cage bars.

  The former employee explained one instance of cruelty witnessed, One of the trainers went into a pen and held down a dog with his knee. He was kicking the dog while he held it down to try to subdue it. Then he started punching it and then he held it up by the throat and said to it: 'So are you going to stop?'"

• In 2009, documents revealed that Interfauna shipped beagle dogs thousands of miles to a South Korean laboratory. Here they were used in experiments where they showed neurological issues and severe discomfort, including struggling to walk, as a result of tests. Others were documented to exhibit [H]ead circling...turning...walking into walls".
• In 1994, NAVS went undercover at Interfauna. They reported bare conditions, minimal stimulation and dogs fearing human contact.

  One investigator commented: In the second unit, a mother gave birth as we watched. She had just bare metal walls, a concrete floor with the thinnest scattering of sawdust...I felt sorry for her. She was shivering: it was difficult to tell whether this was from cold or fear. She had no prospect of help, nor comfort."