Sir Keir Starmer's trip to the UN General Assembly in New York has been overshadowed by a new diplomatic brouhaha with Donald Trump after his office issued a brutal slap-down of a Labour minister.
Home Office minister Angela Eagle told Labour conference delegates on Monday night that Donald Trump was among those who had made "anti-immigrant rhetoric" mainstream in Britain and the West.
She said it was difficult for immigrants to "rise above the constant drumbeat of toxic anti-immigration, anti-immigrant rhetoric that has become emboldened, not only in Britain but across the Western countries."
"I mean, Trump does the same. If you look at some of the memes that he's using with the wall stuff at the moment, it's astonishing, quite the level of vitriol that it has created."
This afternoon, a spokesman for Donald Trump furiously hit back.
Steven Cheung said: "Nobody knows who this random person is or cares what comes out of her mouth.
"Who is she and what does she do?"
The move couldn't have come at a more awkward time for Sir Keir Starmer, who is flying to New York this evening.
It is rumoured that the PM is hoping to meet with Mr Trump and Vice President Kamala Harris, plans that may have been jeopardised by Ms Eagle's comments.
The Prime Minister will further be irritated by the spat, as he hopes to promote Britain's return to "responsible global leadership".
He is expected to tell fellow world leaders: "This is the moment to reassert fundamental principles and our willingness to defend them. To recommit to the UN, to internationalism, to the rule of law.
"Because I know that this matters to the British people. War, poverty and climate change all rebound on us at home. They make us less secure, they harm our economy, and they create migration flows on an unprecedented scale.
"The British people are safer and more prosperous when we work internationally to solve these problems, instead of merely trying to manage their effects. So, the responsible global leadership that we will pursue is undeniably in our self-interest."
The Prime Minister has embarked on a self-proclaimed mission of resetting the UK's relationships with overseas allies since winning the election in June.
He is pushing to tie Britain closer to the European Union, arguing his foreign policy goes hand-in-hand with his ambition of driving economic growth in Britain.
Sir Keir will be in New York for two days, during which he will use several interventions to promote "security, stability and prosperity at home".
He will speak at the General Assembly on Thursday, saying it is only by being a reliable and trusted international partner, working together to solve global problems such as war, poverty and climate change - that we can build a safer and more prosperous UK.
The meeting comes at a perilous time, as the Government issued warnings this evening to Brits in Lebanon telling them to get out.
