Donald Trump arrives at Downing Street with other world leaders for Nato reception hosted by Boris Johnson after they all met royals at Buckingham Palace

Donald Trump joined Boris Johnson at a Downing Street reception for world leaders tonight to cap off the first full day of Nato’s 70th anniversary summit in London.

The Prime Minister, who has been cautious to downplay his friendship with the President over fears his divisiveness could damage Conservative electoral prospects, did not greet his US counterpart on the steps of Number 10 for the traditional handshake. 

Instead, Mr Trump and his wife Melania posed in front of the famous black door together before heading inside to meet Mr Johnson who was waiting across the threshold. 

No bilateral meetings had been agreed between the White House and Downing Street prior to the summit, which comes in the middle of a crunch election campaign with less than two weeks until Britain goes to the polls.

Conscious of how voters typically loathe meddling by foreign leaders in their elections, Mr Johnson has been hoping the notoriously brash and unpredictable President does not do, say or tweet anything that could sink his campaign.

But today Mr Trump waded into an ongoing Tory-Labour row by pouring cold water on Jeremy Corbyn’s main campaign attack line which claims the US is eyeing up the NHS in a post-Brexit trade deal with the UK. 

The President and First Lady had been whisked down Whitehall from Buckingham Palace for a reception hosted by the Queen and attended by the Duchess of Cambridge.  

And the President and First Lady earlier this evening had tea with Prince Charles and Camilla at Clarence House before arriving at Buckingham Palace amid heavy security. 

For the whistle-stop tour of engagements, Melania wore a yellow £4,700 Valentino coat to keep the British cold at bay teamed with fuchsia heels, while the president opted for a dark blue suit, white shirt and blue tie. 

Although Mr Johnson was pictured preparing to welcome the President and First Lady to Number 10 tonight, it is not clear if the two leaders spoke privately during the reception.

The Prime Minister has been keen to dodge photographs with Mr Trump so not to give his political rivals ammunition to make accusations of him cosying up to the controversial leader.

However the President, who has previously stated his admiration for Mr Johnson, today heaped praise on him once more when he said: ‘I think Boris is very capable and I think he’ll do a good job.’

The Duchess of Cambridge was spotted departing for the function this evening while the US president enjoys afternoon tea with the Prince of Wales and the Duchess of Cornwall.  

This is while Camilla cut an elegant figure in a red dress and black blazer with Prince Charles wearing a navy pin stripe suit. 

Other world leaders at Buckingham Palace tonight include Turkish President Recep Tayyip Erdogan and his wife Emine and Chancellor of Germany Angela Merkel and Prime Minister of the Netherlands Mark Rutte.

The Duchess of Cambridge is expected to play a key part in tonight’s event, as her husband, Prince William today joined a British navy crack team protecting oil tankers against hostile Iranian forces. 

Tonight the Queen also wowed in a green dress and accessorised with a emerald green shawl, a pearl necklace and pearl earrings. She seemed in good spirits following rumours from cruel social media trolls who had speculated her death.

Trump’s visit to the palace comes after Jeremy Corbyn vowed to confront him tonight after the US president took a wrecking ball to his claims the US want to seize the NHS.

The Labour leader said he will warn the president ‘public services are not for sale’ at a NATO reception being hosted by the Queen later.

The threat comes despite Mr Trump moving to kill the veteran left-winger’s main election attack line by flatly dismissing the idea he wants a post-Brexit trade deal to open the health service to American companies and push up drugs prices.

Speaking as he ran the gauntlet of a NATO summit in London, Mr Trump insisted the US ‘wouldn’t touch the NHS if you gave it to us on a silver platter’. 

This evening, world leaders started to arrive at Buckingham Palace, where they will be hosted by the Queen to mark 70 years of the Nato alliance. 

Despite initially saying he had ‘no thoughts’ on the UK ballot, Mr Trump also lavished praise on Boris Johnson for doing a ‘great job’ and made clear he had always supported Brexit.

The dramatic spat came as Mr Corbyn tries to ‘weaponise’ the President’s arrival as he desperately works to claw back the Tories’ poll advantage. A poll today found the Conservatives are 12 points ahead, enough for a comfortable majority.

Yesterday Labour released an extraordinary video blaming Britain’s close relationship with the US for the London Bridge terror attacks – despite pleas to avoid politicising the atrocity. 

Today the veteran left-winger has written to Mr Trump urging him to guarantee that the NHS will not form part of a trade deal.

In series of interviews, Mr Corbyn said he was planning to challenge the president over the health service at a Buckingham Palace reception this evening. 

He said he would tell Mr Trump: ”Welcome to this country. I hope you’ll understand how precious our national health service is, and in any future trade relationship with the USA, none of our public services are on the table, none of our public services are for sale and investor state protection is not acceptable to our government when we’ve won this election.’  

However, Mr Corbyn dodged when pressed over allegations leaked documents on US-UK trade discussion had been circulated by Russia. He claims the details showed the NHS was ‘on the table’ – although the Tories have ridiculed the idea. 

This is while Prime Minister Boris Johnson today hosted Turkish President Recep Tayyip Erdogan, French President Emmanuel Macron and German Chancellor Angela Merkel, for talks in Downing Street amid growing tensions within the Western alliance over the conflict in Syria.

The US President took questions from reporters before a meeting with NATO Secretary-General Jens Stoltenberg.

At first he refused to be drawn on the election, saying he was ‘staying out’ and ‘didn’t want to complicate it’.