A Richmond-based company, that produces caviar sold at Harrods and Fortnum & Mason, is being investigated after one of its most desired products was found to contain eggs from an “inferior” fish.

Kings Fine Foods, which is Britain's largest supplier of caviar, is being investigated by Richmond Council after an analysis revealed that a tin marked as Sevruga contained roe from a cheaper breed whose eggs are considered inferior.

A Richmond Council spokeswoman said: “King’s Fine Food are a distributor of caviar and based within our borough.

"We are currently carrying out an investigation, following anomalies during our routine sampling programme.

"It would be inappropriate to comment further until the investigation has concluded.”

The company, in Millfield Road, has removed the product, which sells for £1,280 per kg, and sent all its other caviar products for DNA testing.

The Environmental Health Association (EHA) took four random samples of different caviar for testing at the end of October 2012.

In December 2012 an EHA officer told Kings about the different product in the Sevruga tins and the company contacted their suppliers, who insisted this was wrong.

However, after waiting for this proof it did not arrive and the company removed all sales of Sevruga at the beginning of March. 

A Kings Fine Foods spokeswoman said: “As a result of this incident, we have written to all our other suppliers, asking for DNA tests to support our purchasing. With the exception of a farm in Canada, all the suppliers who have responded to us have informed us that they consider DNA testing unnecessary as they are experts in the farming of the fish concerned.

“Although we value and take very seriously these assurances, we have already taken the decision to implement our own DNA testing programme, to ensure that our customers can be certain of both the nature and quality of caviar that they buy from us. 

“The results of our testing programme will be regularly published on our website and sent to all our trade customers. I am sure that all the other caviar dealers in the UK will now want to follow suit in this regard.”

Buckingham and Kensington palaces, the Ritz hotel, Liberty, the Grouchop Club and Claridge's are among the company's customers.