The former US ambassador to the EU has made a withering attack on Donald Trump over his treatment of the country's outgoing top diplomats.
Anthony Gardner says he was told to leave office by midday on 20 January with no grace period.
"This was a breach of normal procedure and I cannot hide my concern at the way this was done," he said.
He was asked to leave even though no replacement ambassador was in place.
His comments come amid mounting speculation that Professor Ted Malloch, a US academic based in the UK, will be Gardner's successor in Brussels.
Gardner left office last week after being told there would be "no exceptions" for ambassadors requesting to extend their posting past inauguration day last Friday, in contrast with other Presidents, even for ambassadors with young children. The same instruction was given to all foreign US ambassadors.
Gardner, who had been appointed by former President Barack Obama, is one of about 80 ambassadors for countries and agencies who have been discarded.
The move threatens leaving many countries without Senate-confirmed envoys for months and cutting off a direct line to the President.
Gardner said having left office after three years in the post he now felt "unshackled" and able to "speak out."
He said he received the demand to go in an email on 23 December, adding, "The instruction to leave was like a guillotine being swung. Of course, it was not a question of wanting to hang around but it was wrong that my staff were also given such short notice, an inappropriate period, in which to pack up and leave."
Meanwhile, the man tipped to be Trump's new ambassador to the EU has told British government advisers they should read the President's business book 'The Art of the Deal' before starting trade negotiations with the US.
Professor Malloch, a long-time supporter of Trump who also attended his inauguration, is understood to have spoken to Downing Street staff after Theresa May's Brexit speech last week.
Based in Britain at the Henley business school, Malloch said in an interview that he believed the British Prime Minister had had her "finest hour" during her speech at Lancaster House where she said the UK would not be seeking to remain a full member of the EU's single market.
Malloch, who has had formal meetings at Trump Tower over the past few weeks regarding the EU ambassador post, said he would describe Trump's approach to the EU as "sceptical" but not anti-European.
"I think the European project will be redefined, with Brexit and other exits to come. It's not as a result of an American heavy hand though. It's a result of political forces in Europe," he told the Guardian.
"In the [French election] runoffs now we most probably have a right nationalist and a right Thatcherite. No one could have predicted that three or four months ago.
"I think his preference is for bilateral relationships and trade deals, to the degree that is possible."
Meanwhile, Trump's first wife Ivana has reportedly voiced her interest in becoming ambassador for the Czech Republic.