Donald Trump has heaped praised on his “friend” Boris Johnson and suggested the UK is in “turmoil” in the wake of his resignation. 

Ahead of his controversial trip to Britain, the US President appeared to undermine Theresa May by paying tribute to the former Foreign Secretary just hours after he quit over Brexit.

Trump also compared the UK unfavourably to Russia, saying that his planned talks with Vladimir Putin next week would be “the easiest of them” in coming days.

Speaking on the White House lawn as he prepared to board his Marine One helicopter ahead of a week-long trip to Europe, the President dispensed with diplomatic niceties as he waded into the issue of May’s Cabinet troubles.

Trump, who is heading to a Nato summit with a demand that EU countries pay more for their defence, said Johnson had been backing his Presidency.

“Boris Johnson is a friend of mine, he’s been very, very nice to me, very supportive,” he said.

“And I maybe will speak to him when I get over there. I like Boris Johnson, I’ve always liked him.”

On his own trip to the US earlier this year, Johnson said that Trump could be eligible for a Nobel peace prize if he pulls off a nuclear disarmament deal with North Korea.

Asked if Theresa May should remain in power, Trump replied: “That’s up to the people. 

“I get along with her very well, I have a very good relationship. That’s certainly up to the people, not up to me.”

Following the Nato summit in Brussels, the President will travel to London for a four-day ‘working visit’ that will include tea with the Queen, bilateral talks with May at her country house retreat and golf in Scotland.

Trump was asked about the UK and replied: “The UK, that’s a situation that’s been going on for a long time. I have Nato, I have the UK, which is in somewhat turmoil, and I have Putin.

“Frankly, Putin may be the easiest of them all, who would think? Who would think? But the UK certainly – they certainly have a lot of things going on.”

Johnson has changed his tune on Trump since the pair clashed in 2015 when the then Presidential candidate claimed London had ‘no go’ areas where Islamist radicals were dominant.

At the time, Johnson was Mayor of London and said Trump was talking “complete and utter nonsense”.

“The only reason I wouldn’t go to some parts of New York is the real risk of meeting Donald Trump.”

Asked about Trump’s remark that the UK was ‘in turmoil’, the Prime Minister’s official spokesman said: “The Prime Minister looks forward to showing Donald Trump the UK and talking to Donald Trump about the UK and is confident that he will leave with a very positive view.”

Pressed about the President’s comparison of May with Putin, the spokesman added: “I interpreted that as being delivered in humour.”

Labour MP Alison McGovern told HuffPost: “These frankly shocking comments show even more why it’s a good thing that Boris Johnson is no longer in his job. Donald Trump is a President whose values at not those of the British people.”

Earlier, Mayor London Sadiq Khan defended his decision to approve a giant ‘Trump baby’ balloon that protestors will float over Parliament Square during the President’s visit this Friday.

A series of mass demonstrations are planned for the trip, stretching from London to Glasgow and Blenheim Palace in Oxfordshire, where Trump will be hosted for a business dinner.

Khan said: “Are you honestly saying the right to protest.. is limited by the ridicule it may cause someone? We can’t curtail our right to protest.” 

Asked on ITV’s Good Morning Britain programme if he would have endorsed a 20ft blimp of himself as a pig or Barak Obama in a nappy, he added: “Let me answer that directly. If it’s peaceful and safe, yes. It’s not for me to be censor. It’s not for me to decide what’s in good taste or bad taste.”