Trump's criticizing Theresa May as she hosts him is called 'appalling,' 'rude' in UK The president's first U.K. visit has been overshadowed by his tabloid interview.

LONDON -- President Trump's first visit to the U.K. since he took office has been overshadowed by fallout from a bombshell interview he gave to a British tabloid.

In the interview with the political editor of The Sun, which is owned by media mogul Rupert Murdoch, Trump said Prime Minister Theresa May’s political rival, Boris Johnson, who resigned from her Cabinet this week in protest at her Brexit strategy, would make “an excellent prime minister.”

He also criticized May’s strategy for taking the United Kingdom out of the European Union, saying it would “kill” a potential trade deal between Britain and the U.S.

The interview, published hours after Trump landed in the U.K. on Thursday, effectively poured gasoline, or petrol as it is called in the U.K., on a fiery debate within May's government over how to exit the EU.

The prime minister has for months struggled to walk a fine line in her wafer-thin, minority government between members of Parliament who favor a clear break from the EU and others who want closer ties with the bloc after the U.K. leaves.

The Brexit plans revealed to ministers this week tilted on the side of keeping a close relationship with the bloc, which prompted the resignation of both Brexit Secretary David Davis, and Foreign Secretary Boris Johnson.

Then came Trump's interview with The Sun.

But since the interview's publication, support for May has come from both sides of the political aisle, with many Parliament members taking umbrage at president's criticizing the prime minister while she was hosting him.

Yvette Cooper, of the opposition Labor Party, said: “Trump’s appalling behavior makes me sympathize with Theresa May.”

Another opposition party member of Parliament, Rupa Huq, said on Sky News: “For him to knife her in the back like this is just really rude.”

On the same news broadcast, Sir Simon Fraser, a former head of the United Kingdom's diplomatic service, said: “Condescending comments about the prime minister are unacceptable.”

Politicians in the ruling Conservative Party have been largely avoiding addressing the interview, although some have joined the criticism against the president.

Sam Gyimah tweeted simply: “Where are your manners Mr President?”

George Osborne, a former finance secretary who now is editor of an influential London-based newspaper that usually supports the Conservatives, released an image of its front-page headline: “No, Mr. President”.

And Conservative member of Parliament George Freeman tweeted: “This is why it was the right thing NOT to offer Trump a State Visit. The qualification for a State Visit is to behave like a Head of State.”

However several of May’s ministers have been trying to put out the diplomatic fires, including one from the Foreign Office telling BBC morning radio that the trip has been a “success” so far.

On Friday Trump lavished praise upon May, in a press conference widely seen as an attempt at damage control following the barrage of headlines about the interview with The Sun, and a U.S. President criticizing the British leader whilst on a visit in her own country.

“This incredible woman right here is doing an incredible job," Trump said at the outdoor press conference in Buckinghamshire, England, at the British leader’s countryside retreat. "I have gotten to know Theresa May much better over the last two days than the last year and a half … I think she’s a terrific woman.”