Scores of public figures from the arts, politics, religious groups and academia have called for a historic protest against Donald Trump's state visit and urged the Prime Minister to cancel it.
More than 90 signatures have been added to a letter criticising the Government for attempting to "normalise" the president's divisive agenda.
A second letter says Mr Trump intends to do "ill" with his power, while in a third, dozens of healthcare workers said they were obliged to speak out due to the "jeopardy British people will face under the current transatlantic appeasement spectacle".
The three letters published in The Guardian come after more than 1.8 million people signed a parliamentary petition calling for a state visit to be prevented as it would "cause embarrassment" to the Queen.
One of the letters has been signed by politicians including Liberal Democrat leader Tim Farron, Plaid Cymru leader Leanne Wood and former Labour leader Ed Miliband.
Musicians including Brian Eno, Lily Allen and Paloma Faith, comedian Frankie Boyle, union leaders and researchers have also signed it.
It states: "We are dismayed and shocked by the attempt of the British Government to normalise Trump's agenda.
"People in Britain never voted for this. It is our duty as citizens to speak out.
"We oppose this state visit to the UK and commit ourselves to one of the biggest demonstrations in British history, to make very clear to our Government, and to the world, that this is not in our name."
A second letter signed by director Ken Loach, Mohammed Kozbar of the Muslim Association of Britain, Rabbi Lee Wax and Sabby Dhalu of Stand Up to Racism among others, said the president should not be accorded any form of official visit.
It states: "Trump is, as the president of the richest and most powerful nation on earth, uniquely placed to do good or ill. His first week in office has shown beyond doubt that he intends the latter.
"Most people in Britain want no part of it. They do not expect our Government to condone or celebrate such policies or the values that stand behind them. That is why we say no Trump in Britain."
Dozens of healthcare workers signed a third letter in protest at the PM's failure to respond to Mr Trump's controversial executive orders including the travel ban and repeal of the Affordable Care Act, also known as Obama Care.
They also criticised Theresa May for appearing to be "happy to accelerate the fragmentation and sale of NHS services to US markets".
"As healthcare workers in the NHS, our pledge to do no harm obliges us to speak up about the jeopardy British people will face under the current transatlantic appeasement spectacle," the letter says.
The PM invited Mr Trump to visit Britain later this year during a recent trip to the White House.
Previous presidents have enjoyed banquets at Buckingham palace, formal and informal audiences with the Queen and senior royals and addressed MPs in Westminster Hall.
A petition in support of Mr Trump's planned state visit has attracted more than 250,000 signatures.