Media playback is unsupported on your device Media caption The footage, filmed in night vision, looks at conditions at Furnish Kennels

Secretly filmed footage of a County Tyrone dog breeding firm shows "barbaric" scenes, a senior Scottish government vet has said.

Furnish Kennels in Fivemiletown claims to be the largest licensed dog breeding establishment in the UK.

A BBC Scotland investigation into the lucrative world of dog trading filmed hundreds of breeding bitches in battery-farmed conditions.

The firm's solicitor said the premises are run in accordance with the law.

Image caption Puppies are shown huddled together in trailers outside the main building

Image caption The footage was secretly filmed after dark

The programme, to be broadcast on Wednesday, shows dozens of pups, just weeks old without their mothers, huddled together in disused trailers outside the main building in freezing conditions.

Sheila Voas, chief veterinary surgeon with the Scottish government, tells the programme: "It was barbaric. It was a production line. It was using animals as a commodity."

The establishment is run by brothers David and Jonathan Hamilton.

In a statement issued through his solicitor, David Hamilton said the premises were "maintained and run in accordance with all relevant legislation and regulations in an entirely open and transparent manner".

"All dogs are under the supervision of a nominated veterinary surgeon," he added.

The council responsible for inspecting the kennels said the premises, now called the UK Dog Breeding Academy, were inspected four weeks ago and that no puppies were found to be kept in trailers on site.

Fermanagh District Council said the premises complied with legislation.

The programme looks at the supply of dogs from source to sale, investigating the activities of Scottish couple Brian and Bernadette O'Neill.

It tracks Mr O'Neill's trips to County Wexford in the Republic of Ireland over several months, and hears from a Scottish Society for the Prevention of Cruelty to Animals investigator who says the couple are significant dealers in pups.

It estimates that they are selling about 50 dogs each month, bringing in about £200,000 a year.

The O'Neills were asked to participate in the programme but they declined to do so.

BBC Scotland Investigates: The Dog Factory is shown on BBC One Northern Ireland and BBC Scotland at 21:00 BST on Wednesday 15 April and is available to watch afterwards on iPlayer.