US President Trump has blown into the UK with some tough talk for his former bromance partner, French President Emmanuel Macron, at the beginning of a summit to mark the 70th anniversary of the Nato military alliance.
The US leader touched down in London on Monday evening local time for the anniversary party which will be attended by 29 leaders included in the military alliance that covers more than one billion people around the world.
Speaking at a press conference with Nato Secretary General Jens Stoltenberg, Trump was quick to fire up when asked about President Macron's recent comments that Nato was "brain dead" and countries could no longer rely on the US to come to their aid.
"Turkey responded by saying that he was brain dead which was interesting," President Trump shot back. "I think that's very insulting to a lot of different forces. It has a great purpose."
"That's a very, very nasty statement," the US leader continued. "[France] have a very high unemployment rate.
"You look at what's happened with the yellow vests …. they've had a very rough year. You just can't go around making statements like that about Nato, it's very disrespectful."
Warming to this theme, the US leader warned he has plans to slap additional taxes on France in response to European Union tariffs.
"They have to shape up otherwise things are going to get very tough.
"Nobody needs us more than France. That's why I think when France makes a statement like they did about Nato, that's a very dangerous statement for them to make."
The comments highlight tensions in the successful alliance that has become strained in recent years due to expansion of member states, changing focus and President Trump's transactional approach to foreign policy.
The alliance was formed in 1949 based on deterring the Soviet Union via collective defence, where an attack on one member is an attack on all. However in the 70 years since, the demise of the Soviet Union, rise of China and expanded membership to include volatile allies like Turkey has fractured the single voice of the organisation.
German Chancellor Angela Merkel, in the final period of her reign, has played the go-between, trying to keep the Nato leadership train on the rails.
President Trump's wide ranging press conference also touched on the burden of defence spending which has been his major bugbear with the organisation. Trump has successfully forced allies to boost their own share of expenditure but the US remains the largest contributor to the organisation supplying around 4 per cent of GDP each year.
On the upcoming UK election which will be held on December 12, the President almost managed to stick to the script of diplomatic noninterference, saying "I think Boris is very capable and I think he'll do a good job."
When asked about the prospect of Labour leader Jeremy Corbyn becoming Prime Minister, he said: "I can work with anybody, I'm a very easy person to work with."
On the matter of whether the British National Health Service (NHS) would be up for negotiation during a free trade deal with the US, the President said: "I don't even know where that rumour started. If they handed it to us on a silver platter we'd want nothing to do with it.
Nato Secretary-general Jens Stoltenberg said Nato is "agile" and "adapting" to a changing world and allies are stepping up their efforts on burden sharing and helping modernise the alliance.
"We have always been able to unite around our core policies, to protect each other," he said. The anniversary party is not a full-scale summit but is expected to include leaders taking steps to strengthen Nato's global role. On Tuesday evening, UK time, the Queen will host leaders for a reception at Buckingham Palace, ahead of a reception at Downing Street.
She will be joined by the Prince of Wales and the Duchess of Cornwall, the Duchess of Cambridge, the Earl of Wessex, the Princess Royal, the Duke and Duchess of Gloucester and Princess Alexandra, while Prince Andrew will be conspicuously absent.
Karen Donfried, president of the German Marshall Fund think tank, said the 29 Nato allies are approaching this meeting "with a sense of foreboding."
"Few anticipate a gathering that will both unify and stop the growing cracks in cohesion. Alliance leaders carry the responsibility to articulate Nato's common purpose and ongoing relevance. If they do not, Vladimir Putin will be raising a glass in Moscow to the fraught state of the alliance at 70," she said, in reference to Russia's president.
Carnegie Europe think tank's senior fellow Tomas Valasek said the leaders have a responsibility for not undermining deterrence.
"Deterrence is not just about having bombs, bullets, missiles, aeroplanes or these days cyber geeks you can deploy against the adversary. Deterrence is also about communicating that we mean it when we say we're an alliance of 29 and we are ready to respond as 29 when something bad happens," Mr Valasek said.
"Our adversaries are constantly looking for chinks in our armour. For cracks or signs of division. God knows there have been plenty of those," he added.