May's Brexit plan could kill US trade deal: Trump

President Donald Trump has rubbished embattled British Prime Minister Theresa May's Brexit strategy, saying it will probably "kill" the chances of a bilateral trade deal, inviting sharp criticism from MPs, many of whom described it as an insult to the country.

The Brexit strategy spelt out in a White Paper has proved controversial as it led to the resignation of two senior Cabinet ministers, including Brexit minister David Davis and foreign secretary Boris Johnson.

In an interview with the Rupert Murdoch-owned Sun newspaper, Trump became the latest critic of May's Brexit plans, which foresee a closer relationship with the European Union (EU) after Britain leaves the 28-member economic bloc next year than many hard-Brexit supporters are demanding.

"If they do a deal like that, we would be dealing with the European Union instead of dealing with the UK, so it will probably kill the deal," the US President told the newspaper in reference to May's Brexit strategy.

Trump also said he had told May how to do a Brexit deal, but: "She didn't agree, she didn't listen to me.

"I told her how to do it. That will be up to her to say. But I told her how to do it. She wanted to go a different route," Trump, who is in London on his first official visit, said.

The US President's interview attracted sharp criticism from British MPs, many of whom described it as an insult to the British prime minister and the UK.

Conservative party MP Sarah Wollaston said Trump was "determined to insult" May, adding: "If signing up to the Trump worldview is the price of a deal, it's not worth paying."

"Our Prime Minister is so weak she still rolls out the red carpet for a man who does nothing but insults her. Humiliating," Opposition Labour party MP Ben Bradshaw added.

In the interview, Trump said he was "cracking down" on the EU because "they have not treated the United States fairly on trading".

Trump described Johnson, one of leading critics and who is seen as a potential challenger to May, as a "very talented guy" and said the former foreign secretary would make a "great Prime Minister".

"I have a lot of respect for Boris. He obviously likes me, and says very good things about me. I was very saddened to see he was leaving government and I hope he goes back in at some point. I think he is a great representative for your country," he said.

In the wide-ranging interview to the tabloid, the US President also took aim at one of his most vocal critics, London Mayor Sadiq Khan.

He blamed the Pakistani-origin mayor for making him feel "unwelcome" in the UK, in light of mass street protests and said he "used to love London".

Khan had authorised protesters to raise a giant helium-filled balloon showing a nappy-wearing Trump next to the British parliament today.

Trump said that Khan was doing a "terrible job" in fighting crime and believed the mayor was responsible for the terror attacks that had taken place in the British capital because he had "done a very bad job on terrorism" as well as a "bad job on crime".

Responding to Trump's criticism of his response to terrorism, Khan said it was "interesting" that the US president "is not criticising the mayors of other cities" which have also experienced terror attacks.

He defended his decision to allow the giant Trump baby inflatable to fly over London, saying: "The idea that we limit the right to protest because it might cause offence to a foreign leader is a slippery slope".

Trump went on to claim that the UK and the rest of Europe was "losing its culture" because of immigration.

"Allowing the immigration to take place in Europe is a shame," he said.

The interview was conducted in Brussels before the US President and First Lady, Melania, arrived in the UK yesterday afternoon.

At a red-carpet reception at Blenheim Palace, Oxfordshire, last evening Prime Minister May made a call to strike an "unprecedented" post-Brexit trade deal between the US and UK.

"Now, as we prepare to leave the European Union, we have an unprecedented opportunity to do more. It's an opportunity to reach a free trade agreement that creates jobs and growth here in the UK and right across the US," May said at the gala dinner she hosted at the 18th century ancestral home of Britain's war-time Prime Minister Winston Churchill.

Meanwhile, White House spokesperson Sarah Sanders sought to do some damage control over the controversial interview, saying Trump "likes and respects Prime Minister May very much" and added that he had "never said anything bad about her".