The aftershocks of the embarrassing release rumbled through the corridors of the British Parliament and government - with lawmakers and officials unsure whether the ambassador, Sir Kim Darroch, would survive to finish his assignment in 2020.
On Monday, May's spokesman said the British ambassador retained the prime minister's "full faith" and that there was no move to bring Darroch home.
May's spokesman also stressed that the British leader did not share in her ambassador's withering critiques.
But May is on her way out - shoved from power by her own party for her failure to deliver Brexit.
And so there was speculation in British political circles about whether the leak might have been designed to push the Europhile Darroch out of Washington, to be replaced by someone more to Trump's liking when a new prime minister forms a new government later this month.
Trump tweeted his displeasure on Monday - and more than hinted that he is looking forward to a change: "I do not know the Ambassador, but he is not liked or well thought of within the U.S. We will no longer deal with him. The good news for the wonderful United Kingdom is that they will soon have a new Prime Minister."
International Trade Secretary Liam Fox said he would issue an apology to Ivanka Trump when the two met in Washington on Monday. It was not revealed why the British minister, whose job is to negotiate a new free-trade deal with the United States, was meeting with the President's daughter and special adviser.
Fox stressed that he was outraged, not at Darroch, but at the unknown leaker, whom he called an "unpatriotic" underminer of the special relationship between the United States and Britain.
Fox said he suspected that the perpetrator was either a member of the civil service or the "political class" - which did not do much to narrow the number of possible sources.
The cables were not hacked. Excerpts of the correspondence were published in a report by the Mail on Sunday tabloid. On Sunday, British officials confirmed the authenticity of the cables.
"This is such a damaging, potentially damaging, event, that I hope the full force of our internal discipline, or even the law, will come down on whoever actually carried out this particular act," Fox told the BBC.
The leak comes as former foreign secretary Boris Johnson and current Foreign Secretary Jeremy Hunt campaign among 160,000 Conservative Party voters to be the next party leader and prime minister.
On Monday, Hunt held a news conference announcing the leak investigation and making his own thoughts on Trump known - stressing that he, too, did not share Darroch's disparaging impression of the American president as "insecure" and "incompetent".
In a 2017 memo, Darroch wrote: "We don't really believe this Administration is going to become substantially more normal; less dysfunctional; less unpredictable; less faction riven; less diplomatically clumsy and inept."
Hunt couched that as "a personal view, and there will be many people in this building who don't agree with that view, and indeed I don't agree with some of the views that we saw in those letters".
"I think the US administration is highly effective," Hunt said, "and we have the warmest of relationships and a partnership based on standing up for shared values."
But Hunt - alongside many in British diplomatic corps, active and retired - stressed that the cables were meant for internal circulation for a limited number of eyeballs.
"So I think it's very important that our ambassadors and high commissioners around the world continue to feel that they are able to express those frank views," Hunt said, praising the British Foreign Service as "one of the best diplomatic networks in the world".
Many commentators also observed that Darroch's reportage was not that different from what could be read in almost any US newspaper.
The trove of sensitive material was leaked to a prominent political journalist, Isabel Oakeshott, who also happens to be close to leading hard-line Brexiteers. They include radio show personality and politician Nigel Farage - whom Trump once suggested would make a fine British ambassador. Oakeshott was the ghost writer behind Brexit funder Arron Bank's book The Bad Boys of Brexit.
In her reporting, Oakeshott did not reveal the source of the leak.
But she offered what might be clues on Twitter.
Oakeshott posted: "Enjoying the conspiracy theories. Isn't it much simpler? In the absence of government, the civil service becomes politicised. . . ."
She also wrote: "Too many civil servants rubbishing Brexit - that's why the #washingtonfiles leak happened' suggests @Nigel_Farage. Sounds about right."
She retweeted Farage's call for Darroch to be fired.
Asked Monday by BBC Radio whether he might replace Darroch as ambassador, Farage replied: "No. I don't think I'm the right man for that job."
He joked that he was obviously not very diplomatic.
"But, am I the right man to try and help forge a better, closer relationship in terms of intelligence, security and trade with an administration that contains friends of mine?" Farage said. "Yes, I could be very useful."
