Footage taken of puppies inside a centre that breeds them for experiments shows them in barren cages and displaying signs of extreme stress, according to experts and activists.
The clips, seen by The Independent and thought to be the first detailed video shot at MBR Acres in 50 years, show beagles confined to cages where the floors are soiled with their waste.
Animals are seen carrying out repetitive movements, which vets say signals frustration.
And high-pitched calling by numerous dogs, apparently in distress, is heard continually in the video.
The only effort seen in the clips at entertaining the puppies is a ball on a chain but it appears to have been tucked out of the way.
One vet who watched the footage likened the scenes to those inside pig factory farms.
The centre in Huntingdon, Cambridgeshire, run by Marshall BioResources, breeds an estimated 2,000 or more beagles a year to supply universities and private laboratories where experiments are conducted for medical and veterinary research.
Protesters have been demonstrating outside the camp since last summer, demanding its closure, and singer Will Young last year chained himself to the gates.
The company insists it operates to high animal-welfare standards and that it is inspected regularly by the Home Office, which licenses it, to ensure guidelines are met.
An inspection last June found no breaches of codes or legislation.
Advocates of animal testing for medical and veterinary research say it has led to life-changing discoveries, from new medicines and vaccines to transplants, anaesthetics and blood transfusions.
But in one clip, a dog is seen repeatedly running back and forth in the same way – “stereotypical” behaviour seen in animals captive in zoos and aquariums, and brought on by the inability to either escape or behave naturally, according to an animal behaviour expert from Winchester University.
Andrew Knight, professor in animal welfare, said the puppies’ behaviour was just like that of “confined animals under stress”.
“The puppies display pathological repetitive behaviours typical in confined animals whose needs are not being met; many can be seen pacing the same loop up and down, in a similar manner to how an enclosed zoo animal might behave,” he said.
Protest coordinator John Curtin claimed the beagles barked continually and alleged that even people across the road from the centre could hear the “constant, extremely loud barking of the dogs and often shrieking and whining”.
Alice Brough, a vet-turned-campaigner, said: “The facilities and level of care apparently provided to these dogs would, in my opinion, not fully take into account their physiological and ethological needs; significant adverse behaviours are evident in multiple dogs to suggest this.”
The government code of practice guidelines on noise, comfort, space and activities were poorly adhered to from what can be seen in the footage, she claimed.
“The conditions and associated issues are starkly reminiscent of pig factory farms. There is only a small amount of substrate – what appears to be sawdust – provided on some areas of flooring.”
Protesters at what is known as Camp Beagle outside say the smell is overpowering.
Mr Curtin claimed that after months of monitoring staff movements, protesters had concluded the pups were left alone for 15 hours on weekdays and longer at weekends.
“This footage is not selected from months of surveillance – it is selected from a random capture of around 20 minutes in total,” he said.
“As far as we are concerned, it verifies the conditions are as expected of an establishment where dogs are raised in prison conditions and appear never to leave the pens or go outside. From our monitoring, we know that the howling never changes to a playful sound.”
He added that the dogs get no natural light, only artificial lights that come on at 6am and go off at 6pm. The code of practice does allow natural light to be totally excluded.
MBR says the animals do not go outdoors because they have to be pathogen-free.
Government sources say banning animal testing in the UK could lead to more testing abroad but the protesters dispute this.
“The UK’s secrecy level is the highest and the standards are the lowest. Most people are not even aware this practice continues. They think it was all banned decades ago,” Mr Curtin said.
Earlier this month, protesters claimed air vents to the outside had been blocked so the barking and whining could not be heard.
When The Independent asked MBR about this, the company replied by saying the vents helped regulate temperatures inside, which had met the code of practice at all times.
That guidance states animals “be given a degree of control and choice over their environment to reduce stress-induced behaviour” with appropriate enrichment.
“It is advisable to remove all excreta and soiled materials from all areas used by dogs at least daily, and more frequently if necessary,” it says, and “dogs shall where possible be provided with outside runs”.
“Consideration should be given to the inclusion of windows in holding rooms, since they are a source of natural light and can provide environmental enrichment.”
A spokesperson for MBR Acres said: “The new footage does not show any irregularities but does show healthy and content dogs in a regulated breeding establishment who are well cared for by a team of trained and dedicated staff.
“The dogs are typically noisy only for brief spurts, for instance when surprised by outside noises.
“Some of the footage shows animals lying down, which is unsurprising for early morning or late evening filming.
“The animals are very obviously in excellent condition, which would be expected for a regulated business staffed almost exclusively with animal care experts.”
Until legal requirements change, the company will continue to breed animals for medical research, the spokesperson said.
They added that animals are used when to not conduct the research would result in greater suffering for the public, clinical trial volunteers, pets and wild animals.
“We remain proud of what we do every day because our work results in dogs that are healthy and well habituated for their vital role of preventing and treating greater suffering.”