Trump hails America's "most special relationship" with Britain as PM hits it off with President

He repeated his view that the use of torture worked but, in a significant move, made clear he had delegated the matter to James Mattis, the Defence Secretary, who is opposed to it.

Read more: Sturgeon should ask Trump for help on EU, says former SNP leader

In almost an hour of talks ahead of a working lunch with the President, the Prime Minister appeared to have made some progress on key policy issues which have threatened to divide them.

A key moment came when, referring to Nato, she declared: "Today we have reaffirmed our unshakeable commitment to this alliance.” Turning to her host, she added: "Mr President, I think you confirmed that you are 100 per cent behind Nato." Mr Trump had caused alarm in the West after previously describing the alliance as "obsolete".

In what will be regarded as his most presidential performance so far, Mr Trump heaped praise on what he defined as America's "most special relationship" with Britain, describing Mrs May's visit, the first of any foreign leader since the 45th President took office, as a "great honour".

Read more: May's visit to Trump branded "terrible mistake" by Cable

After showing the PM the bust of Winston Churchill restored to the Oval Office, Mr Trump said the alliance between the UK and US was "one of the great forces in history for justice and for peace," declaring: "We pledge our lasting support to this most special relationship."

Mrs May was equally courteous and turned to her host to say: ‘I’m delighted to be able to congratulate you on what was a stunning election victory.

"The invitation is an indication of the strength and importance of the special relationship that exists between our two countries; a relationship based on the bonds of history, of family, kinship and common interests."

As expected, the PM took the opportunity to confirm that the Queen had extended an invitation of a state visit to the President and she confirmed that he had accepted. It is thought that when Mr Trump visits the UK, possibly in the summer, he will travel to his "beloved Scotland," raising the prospect of a meeting with First Minister Nicola Sturgeon.

Earlier perhaps in a sign that the two leaders had indeed hit it off and the special relationship was in rude health, the PM and the President briefly held hands as they walked down a ramp through the colonnade walk.

Read more: Alison Rowat on how the PM achieved more than expected, but at the same time not very much

High on the agenda for the leaders’ meeting were Britain's hopes for a swift free trade agreement with the US after its withdrawal from the EU.

Mrs May said they were both "ambitious" for a deal and wanted to "take forward immediate high-level talks, lay the groundwork for a UK/US trade agreement and identify the practical steps we can take now in order to enable companies in both countries to trade and do business with one another more easily".

During the press conference, Mr Trump recalled how he had been ridiculed for predicting the people of Britain would back Brexit.

"I happened to be in Scotland, Turnberry, cutting a ribbon when Brexit happened. We had a vast amount of press there. This was the day before. I said Brexit is going to happen and I was scorned in the press for making that prediction.

"I said I believed it was going to happen because people want to know who's coming into their country and they want to control their own trade and various other things. Lo and behold, the following day, it happened..."

He went on: "Brexit is going to be a wonderful thing for your country. When it irons out, you're going to have your own identity and you're going to have the people you want in your country and you are going to be able to make trade deals without somebody watching you and what you're doing."

He cited a trade deal he had been involved with when he said dealing that with the other country was fast and easy but dealing with the EU was "very tough".

On Russia, Mr Trump admitted he did not know the country's president Vladimir Putin well but he expressed his hope for a "fantastic relationship" between the two nations. The two leaders are due to talk this weekend, the Kremlin confirmed.

Read more: Sturgeon should ask Trump for help on EU, says former SNP leader

The President explained that he could not predict how good a relationship he would have with other countries and smiling added: "Theresa, we never know about those things, do we?" But earlier he predicted he would have a “fantastic” relationship with the PM.

There were lighter moments during the questions and answers with the gathered UK and US journalists.

Mr Trump joked after receiving a grilling from the BBC's political editor Laura Kuenssberg.

The Scot asked: "Mr President, you've said before that torture works, you've praised Russia, you've said you want to ban some Muslims from coming to America, you've suggested there should be punishment for abortion.

"For many people in Britain those sound like alarming beliefs. What do you say to our viewers at home who are worried about some of your views and worried about you becoming the leader of the free world?"

Pointing to Ms Kuenssberg and turning to Mrs May, the President said: "This was your choice of a question?" Leaning in to the microphone with a smile, he added to laughter from the reporters: "There goes that relationship."

Meantime, Mr Trump presented Mrs May with a picture of his illustrious predecessor Abraham Lincoln as a gift on her visit to the White House. The PM gave her host a traditional Scottish cup of friendship, known as a quaich, reflecting the President's Scottish ancestry as the son of Mary MacLeod from the Isle of Lewis.

Earlier, the PM, dressed in sombre black, paid her respects to the military dead of the US at Arlington National Cemetery.

She laid a wreath at the Tomb of the Unknowns at the Virginia cemetery, which holds the remains of unidentified US troops from the First and Second World Wars, as well as the Korean conflict.