Boris Johnson's claims that the EU forces smoked kipper producers to pack their fish with an "ice pillow" are false, with the relevant food safety rules being written in Britain rather than in Brussels.

Mr Johnson wielded a packaged smoked kipper above his head at the final Tory leadership hustings on Wednesday and promised to cut Britain free of Brussels "regulatory overkill" and red tape after Brexit.

He was handed the kipper by a newspaper editor, who claimed he had been sent the fish by an Isle of Man fishmonger who complained of the cost of the Brussels-imposed ice pillow.

But the rules that force the deployment of the pillow are British rules. The EU does not have the power to regulate the sales of smoked fish by business directly to customers but only from businesses to businesses.

There are EU rules to ensure food safety but no requirement in any Brussels legislation for the controversial ice pillow. Brussels only fixes the temperature for sales of fresh fish and not smoked.

“The sale of products from the food business operator to the final consumer is not covered by EU legislation on food hygiene," a European Commission spokeswoman told the Telegraph

“The case described by Mr Johnson falls thus purely under UK national competence.”