May, facing intense pressure to cancel a planned state visit by Trump, was forced to address the controversy in person after the President criticized her on Twitter. But she insisted the US-UK relationship would survive the storm, and suggested the visit by Trump would go ahead.
As the extraordinary diplomatic clash stretched into a second day, the British ambassador to the US revealed he had expressed concerns to the White House about the affair. Trump also faced an unprecedented barrage of criticism in UK Parliament, where MPs variously called him "racist," "fascist" and "evil." Some suggested he should quit Twitter.
Asked about Trump's actions on a visit to Amman, Jordan, May said: "I'm very clear that retweeting from Britain First was the wrong thing to do. Britain First is a hateful organization. It seeks to spread mistrust and division in our communities. It stands against common British decency," she said.
But May declined to rescind the offer of a visit. "The invitation for a state visit has been extended and has been accepted. We have yet to set a date."
The controversy began on Wednesday morning when Trump shared three videos posted on Twitter by Jayda Fransen, the deputy leader of Britain First.
Amid outrage in the UK, May criticized the President through her spokesman. That prompted a rebuke from Trump on Twitter: "@Theresa_May, don't focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom. We are doing just fine!"
On Twitter, the British ambassador to Washington, Sir Kim Darroch, said he had been in touch with the Trump administration. "British people overwhelmingly reject the prejudiced rhetoric of the far right, which seek to divide communities & erode decency, tolerance & respect," he wrote in a post on Thursday. "British Muslims are peaceful and law abiding citizens. And I raised these concerns with the White House yesterday."
Delete your account
Members of Parliament from all parties lined up to criticize Trump in the House of Commons on Thursday. Labour MP Stephen Doughty said: "This is the President of the United States, sharing with millions, inflammatory and divisive content" by someone "who represents a vile, fascist organization seeking the spread hatred and violence in person and online."
British MP: Trump retweeted group equal to KKK
British MP: Trump retweeted group equal to KKK 01:29
Doughty added that, by sharing the tweets Trump was "either a racist, incompetent or unthinking. Or all three."
Another Labour MP, Chris Byrant, said the US President should face arrest if he came to the UK. "The Prime Minister should make it absolutely clear that if Donald Trump comes to this country, he'll be arrested for inciting religious hatred and therefore he'd be better off not coming at all."
Some MPs said Trump should quit social media. Conservative MP Peter Bone said: "Wouldn't the world be a better place if the Prime Minister could persuade the President of the United States to delete his Twitter account?"
Responding to Bone, Home Secretary Amber Rudd replied: "I'm sure many of us might share his view."
Speaking earlier, London Mayor Sadiq Khan said Trump's latest outburst meant it had become "increasingly clear that any official visit at all from President Trump to Britain would not be welcomed" and urged May to call it off.
"President Trump yesterday used Twitter to promote a vile, extremist group that exists solely to sow division and hatred in our country," Khan said in a statement.
'Presidents come and go'
Justine Greening, a British cabinet minister, addressed the controversy in a round of UK media interviews on Thursday morning. Greening said she did not agree with the tweets, but said the relationship between the two countries would survive Trump.
"In the end, our relationship with the United States has a longevity to it that will succeed long after presidents come and go," she told the BBC.
UK cabinet minister Justine Greening
Brendan Cox, the husband of murdered British lawmaker Jo Cox -- whose killer reportedly shouted "Britain first" as he stabbed her -- said Trump had "become a purveyor of hate."
Cox told CNN's Anderson Cooper on Wednesday evening: "This is like the President retweeting the Ku Klux Klan. This is not a mainstream organization and for the President of the United States, our greatest ally as a country, to be retweeting, to be providing a microphone to those voices."
Trump's rebuke to May was originally addressed to the wrong Twitter account, one that had only six followers and has sent only nine tweets.
After deleting his first effort and successfully locating the Twitter handle of the British Prime Minister, he lashed out at Downing Street for its criticism of him retweeting anti-Muslim videos
posted online by Fransen, the deputy leader of Britain First.
Fransen, who was found guilty of religiously aggravated harassment in November 2016 after abusing a Muslim woman wearing a hijab, was jubilant at the attention.
.@Theresa_May, don't focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom. We are doing just fine!
— Donald J. Trump (@realDonaldTrump) November 30, 2017
May in tight spot
May's attempts to woo the US have left her in a difficult position. With a view to strengthening Anglo-US relations after Brexit, May was the first world leader to meet Trump after his inauguration, flying out to Washington to launch a charm offensive.
But the visit went down badly at home. She was widely criticized for taking Trump's hand while walking at the White House, while she was also derided for offering him the invitation of a state visit so early in his presidency.
British Prime Minister Theresa May and U.S. President Donald Trump at the White House in January.
Since then, the decision has come under further criticism as Trump has made a series of interventions in British politics.
In September, he railed against "loser terrorists"
behind the London Underground explosion and suggested that the perpetrator was known to authorities and recruited on the internet, prompting May and a London police spokesperson to publicly rebuke the President.
And in June, soon after news reports surfaced about the London Bridge terror attacks, he seized on the moment to promote the travel ban.
Some 1.8 million people signed a petition earlier this year urging the government to rescind the invitation May made to Trump just weeks after his inauguration in January.