(CNN) Staff at Britain's Blenheim Castle were likely still cleaning up after a lavish dinner Thursday when The Sun dropped the contents of its wide-ranging interview with US President Donald Trump.

Hours into his working visit to the UK, Trump suggested his hosts might lose out in a trade deal to Europe. He criticized British Prime Minister Theresa May's plan for a soft Brexit , while praising her former Foreign Secretary Boris Johnson . He lashed out again at NATO and resumed his feud with London Mayor Sadiq Khan.

Here's what else came up:

Theresa May's proposed Brexit deal

Trump's visit comes at a time of political turmoil for the embattled British Prime Minister, who is fending off criticism over her plans for a "soft Brexit." Trump said her plan would be likely to "kill" any UK-US trade deal.

"If they do a deal like that, we would most likely be dealing with the European Union instead of dealing with the UK, so it will probably kill the deal.

"Because we have enough difficulty with the European Union. We are cracking down right now on the European Union because they have not treated the United States fairly on trading."

He also said he'd told May how to negotiate with the EU, but she ignored him.

"I would have done it much differently. I actually told Theresa May how to do it but she didn't agree, she didn't listen to me."

Former Foreign Secretary Boris Johnson

Boris Johnson quit his role as Foreign Secretary earlier this week, accusing May of allowing an optimistic Brexit vision to become clouded by a failure of ambition.

Trump praised Johnson, and said he would make a "great prime minister."

"Let me tell you, he's a very talented guy. I was very saddened to see that he was leaving government and I hope he goes back in at some point, because I think he's a very ... I think he's a great representative for your country," Trump said.

"I was very surprised and saddened that he was getting out of government. And you lost some other very good people," he continued. "Well, I'm not pitting one against the other, I'm just saying I think (Johnson) would be a great prime minister. I think he's got what it takes and I think he has got the right attitude to be a great prime minister."

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Immigration

Trump declared that immigration has changed the fabric of the continent.

"My father Germany, my mother Scotland. So I have great love for countries in Europe. I think what's happened to Europe is a shame. I think the immigration, allowing the immigration to take place in Europe is a shame. I think it changed the fabric of Europe.

"And unless you act very quickly it's never going to be what it was, and I don't mean that in a positive way. So I think allowing millions and millions of people to come into Europe is very, very sad. I think you're losing your culture."

Queen Elizabeth II

Ahead of his scheduled meeting with Queen Elizabeth on Friday, he described the monarch as a "tremendous woman," praising her ability to avoid embarrassing mistakes.

"She is a tremendous woman, I really look forward to meeting her. I think she represents her country so well. If you think of it, for so many years she's represented her country, she's really never made a mistake. You don't see, like, anything embarrassing. She's just an incredible woman. My wife is a tremendous fan of hers," Trump said.

"(Queen Elizabeth has) a great and beautiful grace about her. No, I look forward (to meeting her). My mother loved the Queen. My mother coming from Scotland, and she'd come back every year religiously, go to Scotland.

"My mother loved the Queen. She thought the Queen was tremendous. Any time the Queen was on television my mother wanted to watch it."

London Mayor Sadiq Khan

There's no love lost between the US President and Sadiq Khan, who Trump said had done a "terrible job" as London mayor.

"Take a look at the terrorism that's taking place. Look what's going on in London. I think he's done a terrible job."

Trump also assailed Khan's record on crime, something he has done regularly in the past. In May he said a London hospital was "as bad as a military war zone hospital ... knives, knives, knives."

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"I think he's done a bad job on crime, if you look. You take a look at your hospital in London, you know what I'm talking about, with all of the horrible things going on there with all of the crime that's being brought in.

"And I think he's not been hospitable to a government that is a very important government. Now he might not like the current President, but again, it's for me I represent the United States. I also represent a lot of people in Europe because a lot of people from Europe are in the United States."

NATO and trade

In the interview, Trump reiterated his frustration with past US administrations, saying they failed to act to rectify the disparity in financial commitment between the US and its NATO partners.

"I'll tell you what, we've had 40 years of presidents and have said that same thing in a nicer way and they got nothing, so, I mean, call it what you want, they're taking advantage of the United States.

"The United States is protecting the, you know, countries, most of which are the EU, and frankly, if you look at it, we get a double-barrel hit. We get hit on trade, where they treat us badly, they have barriers against us trading and you know, strong barriers and tariffs, and we get hit on NATO. So we have a double whammy, a double hit.

"Now it's not the United States, many presidents have come here and said this is not fair and then they go home and go to sleep. I'm not going to let that happen."

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Protests

The President said he used to "love London as a city," but feels "unwelcome" by the protests marking his visit.

"I used to love London as a city. I haven't been there in a long time. I think your mayor has done a terrible job, but when they make you feel unwelcome, why would I stay there?

"And when I say that, I am talking about government because the people of the UK agree with me."

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'England'

During the Trump strayed from the subject of politics to ruminate about the use of the word "England."

"You don't hear the word 'England' as much as you should. I miss the name England," he said.

"I think England is a beautiful name. And you don't hear it very much anymore. But (the football team at the World Cup is) playing as 'England.' That's very interesting. That's good," Trump said.

The four constituent nations of the UK have always represented themselves independently in international soccer competitions.