Political editor David Maddox reports:

If there is one card the UK holds in its dealings with Donald Trump, it is the Royal family.

President Trump reveres the Royal family and the trappings of power that go along with them.

Keir Starmer has already deployed Prince William as a crucial go between with the US president. The prince and president speak almost every week, The Independent has been told.

More important still has been the pageantry. One of the ways that Sir Keir was able to get his trade deal, allow Lord Mandelson to be accepted as ambassador a year ago and other diplomatic successes was to use last year’s state visit as a carrot.

Trump made it clear that he did not want anything to interfere with that and was willing to be more amenable to the UK.

Going forward, the plan to send the King on a state visit for the 250th anniversary of the Declaration of Independence on 4 July has been equally important for Trump and what he sees as his legacy.

So as diplomatic tensions mount and the threat of tariffs increases, this visit and whether it goes ahead will be highly significant.

The prime minister has said he will speak to the US president about Greenland again “in the coming days”.

“I spoke to President Trump yesterday, as I think you all know, and I’ll no doubt speak to him again in coming days,” Sir Keir Starmer said.

“Our offices talk all the time, but we must find a pragmatic, sensible, sustained way through this that avoids some of the consequences that will be very serious for our country.”

Sir Keir Starmer has described the threat of new tariffs from Donald Trump over Greenland as a “moment for the whole country to pull together”.

Speaking at a Downing Street press conference, the Prime Minister said: “A partnership does not mean abandoning principle. That is why it’s important to be clear about who we stand with, what we stand for, and where our interests lie.

“This is a moment for the whole country to pull together, so I warmly welcome the support we’ve had with regards to Greenland and the proposed tariffs from the Leader of the Opposition (Kemi Badenoch). I thank her for her support.

“At moments like this, there will always be people who reach for the performative, who think an angry social media post or grandstanding is a substitute for hard work.

“That’s an understandable instinct, but it’s not effective. It never has been.”

Political editor David Maddox reports:

Some will have wanted Keir Starmer to come out fighting in regards to the tariff threat from Donald Trump over Greenland. It is certainly the approach other like France’s Emmanuel Macron have taken.

But for the prime minister today was about protecting and perhaps saving his primary foreign policy position of being the bridge between Europe and the US.

So the speech involved warm words towards Trump and an emphasis on the daily contact between his office and the White House administration.

But he also had to admit that “we are not going to agree on everything”. And that included taking a firm stance on how the future of Greenland is up to Greenlanders and Denmark.

There was a reminder that “a trade war is in nobody’s interests”, but this was very much a prime minister crossing his fingers and hoping reason will eventually prevail.

Political reporter Athena Stavrou reports:

Sir Keir Starmer has said he doesn’t believe President Donald Trump’s threats to launch military action in Greenland are genuine.

When asked whether he thought the US president was genuinely considering military force, the prime minister told a press conference: “I don't actually.”

He added: “I think that this can be resolved and should be resolved through calm discussion.

“But with the application of the principles and values that I've set out in terms of who decides the future of Greenland, and making clear that the use of tariffs in this way is going to be is completely wrong.”

Sir Keir Starmer said the US “remains a close ally” despite Donald Trump threatening new tariffs over Greenland.

“The US remains a close ally on defence, on security and on intelligence, on nuclear capability, we’ve worked very closely with the United States, and we must never lose sight of our national interest in that,” he told a press conference.

“But we must stand up for our values. We must be clear about the principles that we are applying here, and we’ll continue to do so on the question of tariffs.”

Sir Keir Starmer has refused to answer questions on whether he believes the King’s upcoming visit to the US should be cancelled.

Earlier, Liberal Democrat leader Ed Davey supported such calls to cancel the visit to mark the 250th anniversary of US independence.

But when asked whether he would speak to King Charles about the trip, the prime minister repeatedly dodged the question.

“In relation to the King and other issues, as I said in my speech, I'm focused on the pragmatic response here,” he said.

“My focus is on what's in the national interest for our country, what is going to best protect workers, families, businesses, and I believe that's the approach that I've set out.”

The UK does not need to “choose between the US and Europe”, despite the threat of new trade tariffs from Donald Trump, Sir Keir Starmer insisted.

The Prime Minister was asked by reporters if the special relationship with the United States was now fractured.

He replied: “I don’t think it’s right for us to choose between the US and Europe. That’s not a new position today. That’s the position I’ve consistently held, as have previous governments.

“Because we are allies with our European partners and allies with the US, and the strength in being able to keep both those alliances has served us well over the last 80 years.”