Queen could revoke Davidstow cheddar royal warrant over river pollution

The Queen could remove the royal warrant from her favourite cheddar cheese after its producer filled a river with a noxious black sludge, the Guardian has learned.

Sources at Buckingham Palace said the warrant for Davidstow cheddar, produced by Dairy Crest, could be removed on environmental grounds after it was fined £1.5m by the Environment Agency.

They said warrants are kept under review, and cheesemakers to the Queen must keep up with environmental standards. Palace insiders added that they can be revoked at any time.

These grants are given by the Queen and Prince Charles to their favoured suppliers, which are then allowed to display the royal coat of arms on their products. It indicates that produce from the companies is enjoyed by the royals, and is used as a mark of quality. Currently, 800 companies hold a warrant, including Bollinger champagne, Waitrose supermarket and Fortnum and Mason.

This move would probably be painful for the Queen, as Davidstow is understood to be her favourite cheddar. It is made by Dairy Crest, which also produces Cathedral City cheese and Country Life butter.

Dairy Crest, now owned by the Canadian firm Saputo, was found over several years to have dumped liquid waste, suspended solids and “biological sludge” into the River Inny in Cornwall, raising its nutrient levels and killing trout and salmon. Part-treated effluent also leaked on to nearby land.

In one incident, treated effluent from the creamery was released into the Inny containing a biocide that killed hundreds of fish. Locals reported that the dairy had left “eggy smells” in the area.

Related: One of UK’s biggest dairy firms fined £1.5m for polluting Cornwall river

The palace has been in talks with the creamery for some time over the river pollution. A spokesperson said: “Dairy Crest made us aware of this issue some time ago and have kept us informed on their actions in response.”

Campaigners have welcomed the potential move, but also called for the Queen and Prince Charles to review royal warrants from other intensive meat and dairy producers. Currently, multiple meat and cheese producers have a warrant.

Rob Percival, the head of food policy at the Soil Association, said: “This case is emblematic of a national issue. Only 16% of inland freshwater bodies in England are close to their natural state, and intensive livestock operations, which provide much of our meat and dairy, are partly to blame.

“These systems tend to create far more manure and slurry than can be safely recycled back to the soil, and inadequate slurry storage, coupled with the over-application of nutrients, often results in river pollution, harming fish and aquatic life.

“Intensive animal farming is making a royal mess of our rivers – it’s understandable that the Queen is considering removing her insignia from the companies responsible.”

Dairy Crest declined to comment on the potential removal of its royal warrant but referred to a statement, in which it offered “sincere apologies” to those who had been affected and said it had carried out work to rectify the factory’s problems.

“Once again, the company would like to express its sincere apologies to those who have been affected. Considerable work has been undertaken to rectify the historic issues to which the prosecution related,” it said. “The company continues to invest significant resources in the best technology, processes and people to further improve its environmental performance and minimise its impact on the local community.”