A rendering of a British flag outside the British Embassy in Washington. (Pablo Martinez Monsivais/AP)

The extraordinary fallout after British Ambassador Kim Darroch’s leaked diplomatic cables were published has served as a stark reminder to diplomats in Washington and elsewhere that much of what they say and write privately could one day find its way into the public eye.

But what has struck some veteran diplomats as most unusual was the lambasting President Trump engaged in after excerpts of Darroch’s unflattering comments, in which the ambassador to the United States called Trump’s administration “inept,” were made public Saturday. They wondered how the episode would affect the way ambassadors communicate moving forward.

Trump responded by tweeting that Darroch was “wacky” and “a very stupid guy” and said his administration would no longer work with him. By Wednesday, Darroch had decided the incident rendered him incapable of carrying out his duties as Britain’s representative in Washington, and he resigned.

Simon McDonald, head of the British diplomatic service, said Wednesday that “people are shaken by what has happened.

“The basis on which we have worked all our careers suddenly feels as if it is challenged,” he told Britain’s foreign affairs select committee. “There is a need for reassurance and reflection."

He also said that diplomats need to be able to communicate candidly with their governments at home. “You were simply doing your job,” McDonald told Darroch in response to his resignation letter on Wednesday.

Trump clearly disagreed. He tweeted that he didn’t know Darroch personally but has “been told he is a pompous fool.” His administration also rescinded Darroch’s invitation to a dinner Monday evening.

The situation escalated so intensely that Darroch’s staff feared Trump could go so far as to declare the senior diplomat “persona non grata” and have him removed from the United States.

In London, British Prime Minister Theresa May came to Darroch’s defense on Wednesday, saying “good government depends on public servants being able to give full and frank advice.

“I hope the House will reflect on the importance of defending our values and principles, particularly when they are under pressure,” she said in an address to Parliament.

Current and former diplomats were debating Wednesday what kind of long-term effect Darroch’s departure could have on the ways in which diplomats communicate to their home countries, from Washington in particular.

Daniel Fried, who served as U.S. assistant secretary of state for European and Eurasian affairs during the George W. Bush administration, said Trump’s response to the leaked cables amounted to the “functional equivalent” of declaring Darroch persona non grata.

Insulting Darroch publicly and saying the White House would no longer work with him was “a nasty diplomatic step and an unfriendly act,” Fried said, adding that Trump had the opportunity to take the high road in a way that would make him look good and Darroch “look foolish.” Instead, his behavior “rather proved the British ambassador’s point now, didn’t it?” Fried said. “It’s a hell of a way to treat friends."

“Frankness is what diplomats are paid to do,” Fried added. “Ambassadors have been making those kind of assessments of American administrations for a long time, and we’ve been doing it about foreign” governments.

Adam Thomson, a former British diplomat who served as ambassador to the United Nations and NATO, said the leak and Darroch’s resignation “will certainly have a short-term chilling effect,” but he expects normal reporting to resume within a few days.

“Diplomats from many countries are already careful about what they put in private communications, not because of Donald Trump or even necessarily because of leaks but because of freedom of information legislation, which means that they have to assume that pretty much everything they write could find its way into the public domain,” he said.

Still, confidentiality is critical to the profession, said Javier Rupérez, a former Spanish ambassador to the United States.

A security breach threatens the “basis of trust” that is essential for diplomats to provide their honest assessments of foreign countries and governments to leaders back home.

“I would be extremely concerned about the fact that I’m not free to offer my own opinions about how I think,” Rupérez said.

If the leak came from a Briton, he predicted the fallout would have a greater impact across the pond. But if the U.S. government bears any responsibility, he said, that could have reverberations for American diplomats abroad.

Still, diplomacy experts say it is unlikely the Darroch incident will pressure diplomats to begin censoring themselves.

Barbara Bodine, former U.S. ambassador to Yemen and current head of Georgetown University’s Institute for the Study of Diplomacy, said the fallout from the 2010 WikiLeaks revelations indicates diplomatic candor lives on even after uncomfortable public exposure.

WikiLeaks made public hundreds of thousands of U.S. diplomatic cables, causing headaches and embarrassment for the U.S. Foreign Service, but diplomats continued to offer unfiltered assessments of dynamics on the ground around the world.

“Yes, you heighten security,” Bodine said. “But you can’t stop doing that which you’re paid to do, which is to know what’s going on and to report it. And the candor part is the critical part.”

Darroch’s comments were “absolutely what could have been expected” from a seasoned envoy, Thomson, the former British diplomat, said, adding most diplomats representing their countries in Washington “have written the same thing.”

It was the Trump administration’s harsh response that was out of the ordinary, he said.

“Ambassadors to some extent aren’t doing their job unless they are prepared to be reasonably forthright not only to their own authorities but also with their host government,” he said. “But if you have a very sensitive government, then there can be unpredictable consequences. It just depends how mature a government wants to be about it.”

Read more:

Trump’s relationship with the U.K. has never been great. This week, it hit a new low.

Read Kim Darroch’s letter of resignation as British ambassador to the United States

Kim Darroch resigns after doing what diplomats have long done: Badmouthing their hosts.