BORIS Johnson has been condemned by the European Parliament's chief Brexit negotiator after comparing French President Francois Hollande to a Second World War guard administering "punishment beatings".

Downing Street and UK Government allies attempted to defend the Foreign Secretary over his use of the colourful language but political opponents tore into him over the comments.

His remarks also threatened to set back Theresa May's attempts to win allies in Brussels as she tries to strike a new deal for the UK after Brexit with senior MEP Guy Verhofstadt branding his comments "abhorrent".

Mr Johnson's controversial comment came during a visit to India and just 24 hours after the Prime Minister warned her Cabinet colleagues about keeping their discipline and avoiding using a “stray word,” that could make the Brexit negotiations more difficult.

The Secretary of State was asked about a reported comment from one of Mr Hollande's aides, who said Britain should not expect a better trading relationship with Europe from outside the EU.

He replied: "If Monsieur Hollande wants to administer punishment beatings to anyone who chooses to escape, rather in the manner of some World War Two movie, then I don't think that's the way forward. It's not in the interests of our friends or our partners."

Mr Verhofstadt, the former Belgian premier who is the European Parliament's lead negotiator on Brexit, said the Foreign Secretary's comments were "deeply unhelpful" and urged Mrs May to condemn them.

Mr Johnson's comments were denounced as "wild and inappropriate" by Labour, which said they would not help Britain negotiate a favourable Brexit deal with the other 27 EU nations.

The PM's spokeswoman brushed off suggestions that the Foreign Secretary should apologise, describing his comments as a "theatrical comparison" and insisting he had not been comparing the French president to a Nazi.

She dismissed the row as a "hyped-up media report" and said she was not aware of any complaint from the Elysee Palace.

"He was making a point. He was in no way suggesting that anyone was a Nazi," she declared.

Asked whether or not it would be better for Government ministers to avoid wartime comparisons as the UK enters sensitive negotiations with its European neighbours, the spokeswoman said: "There is not a Government policy of not mentioning the war."

She said Mrs May and the Government were "focused on taking forward our plan for Brexit".

The Foreign Secretary's brother, Jo Johnson, defended his older sibling, telling the BBC: “He was making a powerful point that we want a rational deal. He was using colourful language to get across an important point which is we've got to look in a cool, calm way at what's in all of our economic interests."

But Liberal Democrat leader Tim Farron said: "This is an utterly crass and clueless remark from the man who is supposed to be our chief diplomat.

"I assume Boris Johnson says these things to deflect from the utter shambles this Brexit Government is in over its plans to take Britain out of the single market.

"But this kind of distasteful comment only serves to unite Europe further against Britain at a time we need friends more than ever," he added.

Ed Miliband, the former Labour leader, tweeted: "Boris Johnson proves once again he's not fit to be Foreign Secretary. Showing you can be supremely clever and yet immensely stupid."

Labour MP Wes Streeting, a supporter of the Open Britain campaign, said: "It seems the Foreign Secretary has been leafing through his well-thumbed copy of How To Lose Friends And Alienate People.

"Nobody who wants to see a good Brexit deal for Britain should welcome these crass comments."

A spokesman for the Secretary of State said: "He was not suggesting anyone was a Nazi and the word never passed his lips. He was simply saying what others have already said - that treating Britain harshly for trying to leave the EU makes no sense and won't deter us."

Downing Street insisted Mrs May had full confidence in her Foreign Secretary.

Asked if she was concerned Mr Johnson's comments had upset the European Parliament's Brexit negotiator, the PM's spokeswoman said: "Lots are going to be said during this negotiation, lots of remarks are going to be made."

Pressed on whether Mr Johnson was a liability, she added: "No. Actually, he is out in India, talking to the Indians about how we can strengthen our trading relationship with India, which will obviously benefit the UK once we leave the EU."

Mr Johnson's comments came as a Cabinet colleague warned of the dangers of "glib" comparisons to the Second World War.

At a Holocaust Education Trust reception, Communities Secretary Sajid Javid said: "We have to push back when people lazily reach for glib comparisons that belittle what happened...calling those we disagree with 'Nazis' or claiming someone's actions are 'just like the Holocaust'. Ultimately, we have to be prepared to do that most un-British of things; we have to make a scene," he added.

In May, Mr Johnson sparked controversy when he suggested the EU was trying to do what Hitler had attempted in seeking to create a European superstate.

In December, the Foreign Secretary was rebuked by No 10 after he accused Saudi Arabia of being among countries engaged in fighting “proxy wars” in the Middle East.