Donald Trump has cancelled his final press conference at the NATO summit in Britain and stormed home after Boris Johnson, Emmanuel Macron and Justin Trudeau were caught on a hot mic mocking him.

The President had already slammed Trudeau as 'two-faced' on Wednesday after the Canadian Prime Minister, Macron and Johnson were caught on video at the Buckingham Palace NATO reception Tuesday evening, appearing to gossip about Trump.

Later in the day the President was caught on another hot mic bragging about his put-down of Trudeau. He said: 'That was funny when I said the guy's two-faced.'

Trump then tweeted about an hour later that he would leave the summit without holding a scheduled press conference, bringing an acrimonious end to the gathering that followed Macron's criticism of NATO as 'brain dead' and Turkish President Recep Erdogan's invasion of northern Syria.

In the video from the reception, which appears to be edited, Trudeau makes the most cutting comments, laughing about Trump's lengthy Q&A sessions with reporters and saying even the president's staff was shocked at some of his actions.

It shows PM Boris Johnson ask: 'Is that why you were late?' as he stoops down and chuckles in disbelief, before Canadian leader Trudeau, swigging from his drink, shoots back: 'He was late because he takes a 40 minute press conference off the top.'

The video then cuts to a later clip, which is without context, and sees Macron pointing furiously before Mr Rutte exclaims 'fake news media' and Trudeau adds: 'You just watched his team's jaws drop to the floor.' He then motions as if his jaw is dropping.

At the press conference today, Trudeau explained his remark about Trump's team jaw dropping was at the president's announcement next June's G7 meeting, which will be hosted by the United States, will be held at Camp David.

'We were all surprised and I think pleased to learn that the next G7 will be at Camp David. I think that was an unscheduled announcement and I think everyone's team, everyone different leader has teams that every now and then have their jaw drop at unscheduled surprises like that video itself for example,' Trudeau said.

He said that came up because his fellow G7 leaders wanted to know the details about their next gathering.

'As we talk to G7 leaders there is an interest in where the next G7 meeting is going to be and I was pleased to share with them the story of how that came about, that we are going to be gathering, apparently, at Camp David,' Trudeau said.

Trump today said during his meeting with Trudeau that next year's G7 meeting will be held at Camp David.

Originally Trump announced it would be held it at his Doral, Fla., golf course but he reversed that decision when even some Republicans criticized it as inappropriate.

'We'll do it at Camp David,' he said. 'It's nearby. It's close. We're going to give good access to the press. ... It will be at camp David which is a place that people like.'

.Trudeau repeated at his press conference Wednesday that he has a strong relationship with Trump.

'The relationship we have with United States is very strong and I have a very good relationship with President Trump and his team,' he said.
But the president did not look amused when reporters asked him about the hot mic video during his meeting with German chancellor Angela Merkel.

'Honestly with Trudeau, he's a nice guy,' the president added after a long pause.

He then explained his theory on why Trudeau said what he did, arguing the prime minister mocked him because he gave Trudeau grief during their sit down on Tuesday about Canada not paying enough in fees to be a member of the NATO alliance.

'I find him to be a very nice guy but you know the truth is that I called him out on the fact that he's not paying 2 per cent and I guess he's not very happy about it,' Trump said.

'He's not paying 2 per cent, and he should be paying 2 per cent. It's Canada. They have money. And they should be paying 2 per cent.

'So I called him out on that, and I'm sure he wasn't happy about that, but that's the way it is. Look, I'm representing the U.S. And he should be paying more than he's paying. And he understands it. So I can imagine he's not that happy. But that's the way it is,' he added.

The pair exchanged words at a photos session for NATO leaders on Wednesday morning but it is unclear what was discussed.

At their Tuesday meeting, Trump noted Canada is 'slightly delinquent' in its NATO payments but added: 'But they'll be okay. I have confidence.'

'When today's meetings are over, I will be heading back to Washington. We won't be doing a press conference at the close of NATO because we did so many over the past two days,' the president said.

Trump had lashed out at Justin Trudeau over video of his jocular discussion with Johnson, and Macron video filmed at a reception attended by The Queen and Kate Middleton at Buckingham Palace last night.

In the clip, Trudeau makes the most cutting comments, laughing about Trump's lengthy Q&A sessions with reporters and saying even the president's staff was shocked at some of his actions.

At a press conference today Trudeau wouldn't answer whether he apologized to the president for his remarks.

He said: 'Last night I made a reference to the fact that there was an unscheduled press conference before my meeting with President Trump and I was happy to take part of it. But it was certainly notable. I've had a number of a good conversations with the president over today and yesterday.'