Any discomfort in Downing Street over the growing relationship and rapport between Donald Trump and Nigel Farage is very likely to have turned to dismay and anger as the latest episode unfolded.
The American president-elect’s suggestion that the Ukip leader become Britain’s ambassador to the US was swiftly shot down by No 10 – which in turn triggered a withering response from Mr Farage. He swept aside insistences from London that there was “no vacancy” for the post, currently held by Sir Kim Darroch, by declaring he stood ready to work with Mr Trump.
The tycoon’s intervention on Twitter, which suggested “many people” would want Mr Farage as their ambassador to the UK and that he would “do a great job” in the role, is extremely uncomfortable for Theresa May and Boris Johnson, her Foreign Secretary.
But Mr Farage had clearly been cultivating a friendship with Mr Trump long before the conclusion of the race for the White House.
The only real surprise in his endorsement by Mr Trump for the ambassadorial role is that it has come so quickly – less than a fortnight after the presidential election.
Mr Farage appears to have inveigled himself into a position on the verge of the corridors of power in Washington faster than anyone would have thought possible.
He has created a strong impression with Mr Trump and, such is the profile Mr Farage has enjoyed in the past two weeks, Americans would be forgiven for thinking that he is a bona fide member of the UK government, rather than a mere member of the European Parliament, who has twice stood down from his role as Ukip leader.
Mrs May was wise enough to keep a relative diplomatic silence during the US election campaign, being careful not to endorse or criticise either candidate.
This was despite earlier criticisms of Mr Trump when she was Home Secretary after he claimed parts of London had become “no-go zones” for the police.
Having played it coy for so long, now that Mr Trump has been elected there is a real danger for Mrs May that if she does not actively pursue the building of a working relationship with him, then Mr Farage will happily step into the breach.
The prospect of Mr Trump testing the temperature of Britain by seeking advice from Mr Farage will set off all kind of alarm bells, well beyond Downing Street.
But rather than give the Trump administration the cold shoulder, Mrs May has to consider the long-standing “special relationship” between Britain and the US, which is much bigger than any one president.
More importantly, if Mrs May fails to build a relationship with Mr Trump it will allow Mr Farage to have even more undue influence than he already has. Some may conclude that it is already too late on this front.
But the UK government has an obligation to try to fully engage with the American president, no matter who he is - and marginalise Mr Farage.