Conservative leadership frontrunner Boris Johnson used a kipper to emphasise what he says is the need to leave the EU. (Photo: AFP)

Brandishing a kipper at a packed campaign event, Boris Johnson railed against EU red tape he said was punishing the producer of the smoked fish -- but Brussels insisted any such regulations are actually British.

Johnson, the frontrunner to become Britain's next prime minister, used the kipper to emphasise what he said was the need to leave ethe EU, while addressing ruling Conservative party members on Wednesday evening.

He said it came from "a kipper smoker in the Isle of Man who is utterly furious".

"Because after decades of sending kippers like this through the post, he has had his costs massively increased by Brussels bureaucrats, who have insisted that each kipper must be accompanied by this -- a plastic ice pillow," he said, holding that up too.

However, Anca Paduraru, EU Commission spokeswoman for Health, Food Safety and Energy Union, disputed his account at a Brussels briefing on Thursday.

"While the food business operator has an obligation to meet the microbiological requirements, the safety requirements to ensure the safety of his food, however the sale of products from the food business to the final consumer is not covered by EU legislation on hygiene," she said.

"So this means that the case described by Mr Johnson falls outside the scope of the EU legislation and it's purely a UK national competence."

She added: "There are strict rules when it comes to fresh fish but these kinds of rules don't apply to processed fishery products -- I'm talking about the temperature and the exact case that he was explaining."

EU Health Commissioner Vytenis Andriukatis tweeted: "Boris, the Isle of Man is not bound to the #EU 'pointless and damaging' *red tape* in #foodsafety that we are proud of because it protects consumers.

"You omitted to say that the Isle of Man is not in the EU. This packaging -- #uk competence. Yet another smoke. #fakenews".

The Isle of Man is not a member of the EU but as a British Crown Dependency, has access to the bloc's customs union which allows the movement of industrial and agricultural goods.

A government spokeswoman said: "The Isle of Man produces some excellent food and drink. We are delighted to see such interest in our world renowned kippers today.

"At present, our producers are required to comply with relevant Isle of Man legislation. The Isle of Man law is closely based on UK legislation and relevant EU food safety regulations.

"Where our goods are exported they are required to comply with standards of the destination market."

Britain's Food Standards Agency was not immediately available for comment.

The producer of the kipper, believed to be Moore's Traditional Kipper Curers, declined to comment.

Kippers are whole fish, often but not always herring, which are split from head to tail, gutted, salted and smoked.

Before he entered politics, Johnson made his name as a journalist in Brussels writing about absurd EU regulations, which drew accusations of not always being true.