Britain's largest funeral company has been accused of piling up naked corpses like "TV sets" in a refrigerated warehouse.

A uncover investigation by current affairs programme Dispatches found Co-op Funeralcare was moving bodies to a warehouse off a busy highway and storing them on racks in a large area, The Sun reported.

Secretly filmed footage showed the corpses tightly packed together. Families of the dead believed the deceased were being kept at funeral homes.

One clip from the Channel 4 programme showed one casket lid being removed as four caskets were crammed into a van, with the nose of the top body almost touching the van's roof.

When the van arrived at a funeral home in Berkshire, staff unloaded the open coffin in full view of neighbouring flats.

In another incident, the wrong body was discovered at the funeral of Mandy Rowden's mother Olwyn.

She had to wait half an hour before her mum's casket was found.

"I was so angry I couldn't cry," she told The Sun.

The company paid her costs and compensation as a result of the mix-up.

The programme also showed staff frantically returning to local funeral homes, a journey of up to 50km, if families asked to see their relative one last time.

Former funeral ombudsman Geoffrey Woodroffe told The Sun he was "shocked" after watching the footage.

"They're treating people as if they're stacking TV sets," he said.

Co-op Funeralcare last year handled 100,000 funerals and made £51 million ($100 million) in profit.

The company said it was "shocked and disappointed" by the information revealed in the documentary.

"We do not believe that the instances shown in the programme are representative of our many caring staff.

"We have however, launched an immediate investigation into the programme's findings and will take any action necessary to ensure our high standards and our policy of enabling clients to make informed choices is maintained," it said.

- © Fairfax NZ News