Boris Johnson, the favourite to replace Theresa May next week as Britain's Prime Minister, has been rebuffed by EU officials for some fishy claims he made on the campaign trail.

Speaking at a Conservative Party hustings on Wednesday night, Johnson brandished a plastic-wrapped smoked kipper to condemn EU's health and safety rules.

The fish, he said, came from a kipper smoker in the Isle of Man "who is utterly furious".

"After decades of sending kippers like this through the post, he's had his costs massively increased by Brussels bureaucrats who have insisted that each kipper must be accompanied by this, a plastic ice pillow. Pointless, pointless, expensive, environmentally damaging. Health and safety, ladies and gentlemen," Johnson said.

He added that when the UK will exit the bloc, it will be able to "end this damaging regulatory overkill."

Watch Boris Johnson's kipper claim in the video below (starts at 28'21)

'Yet another smoke'

But EU officials debunked Johnson's claim on Thursday, with a spokeswoman telling reporters that although the bloc has "strict rules when it comes to fresh fish" they do not "apply to processed fishery products".

"The case described by Mr Johnson falls outside the scope of EU legislation and is purely UK national competence," she said.

The UK's Food Standard Agency requires that "all foods must be delivered in a way that ensures that they do not become unsafe or unfit to eat".

"Foods that need refrigerating must be kept cool while they are being transported. This may need to be packed in an insulated box with coolant gel or in a cool bag," the guidelines continue.

The bloc's Commissioner for Health and Safety, Vytenis Andriukaitis, branded Johnson's claim as "yet another smoke," adding: "#fakenews."

He also pointed out that the Isle of Man — a self-governing British dependency located in the Irish Sea — is not in the bloc.

"Boris, the Isle of Man is not bound to the EU 'pointless and damaging' *red tape* in food safety that we are proud of because it protects consumers," he said in on Twitter.

A history of untruths

Wielding a kipper could be interpreted as a humorous move — a trademark of Johnson's public persona — had it been an isolated incident.

But the 55-year-old has a history of making false and misleading comments, some of which he has lost jobs over, and some he has ultimately capitalised upon.

1. Fabricating a quote for The Times

Prior to the launch of his political career, Johnson worked as a journalist at a number of British news outlets.

He was fired from his job at The Times of London in 1987, having been found to have made up a quote about Edward II "cavorting" with 1st Earl of Cornwall Piers Gaveston at the Rose Palace.

Attributing the quote to his godfather Colin Lucas, who is a historian, the piece ran on the newspaper's front page.

It was then pointed out that by the time the Rose Palace was built, Gaveston had long been dead.

Johnson later said in an interview that the fabrication was his "biggest cock-up", and rather than rectify it immediately, he said he "made matters worse".

"I wrote a further story saying that the mystery had deepened about the date of the castle," he said.

2. A 'fake news exponent' in Europe

Johnson took up a position at the Daily Telegraph after his sacking, where he became the Brussels correspondent between 1989 and 1994.

His tenure saw him labelled as a pioneer of the "Euro myth", something we now refer to more readily as fake news.

Pieces included a report on the introduction of "euro-coffins" or a "banana police force" that would regulate the curve of the fruit.

Speaking to the New Statesmen, former EU external affairs commissioner Chris Patten said Johnson's Brussels position was "one of the greatest exponents of fake journalism".

Similarly, James Lansdale, the BBC's diplomatic correspondent, referred to Johnson in an imitation of Hilaire Belloc’s poem “Matilda”.

Its first two lines began: "Boris told such dreadful lies. It made one gasp and stretch one’s eyes."

3. Extra-marital affair

Fast forward to 2004, and Johnson was fired again from his positions as vice-chairman of the Conservative party and shadow arts minister after being caught lying about having an extra-marital affair.

Multiple reports claimed the politician had had an affair with Spectator columnist Petronella Wyatt, which he dismissed as an “inverted pyramid of piffle”.

Wyatt's mother later confirmed the relationship.

4. Boris and the Brexit bus

Perhaps most famously, Boris was one of the several politicians among Brexit's Leave campaign who peddled the idea that by leaving the EU, the UK would be able to retrieve £350 million a week to be invested in the National Health Service.

The controversial claim was plastered across the side of a Brexit bus as it made the tour around the UK during the campaign to leave the union.

But the morning after the vote, fellow Brexiteer Nigel Farage distanced himself from such a claim, which has been widely disputed.

The UK Statistics Authority later said it was a "clear misuse of statistics".