Donald Trump’s state visit to the UK is expected to be debated in Parliament after senior Conservatives joined hundreds of thousands calling for it to be cancelled.
More than 900,000 people had by Sunday night signed a petition calling for the visit, which is due to take place in the Summer, to be abandoned because of the risk it will “embarrass” the Queen.
Senior Conservatives joined Jeremy Corbyn, the Labour leader, in calling for the visit to be suspended while Mr Trump’s controversial immigration ban is in place.
The internet petition quickly smashed the 100,000 signatures needed to be considered for a debate in Parliament, with at one point more than a thousand people signing each minute.
However Downing Street sources confirmed that Mrs May will not be withdrawing her invitation to President Trump because it remains “substantially in the national interest”.
Ruth Davidson, the leader of the Scottish Conservatives, said that the visit “could not possibly occur” while the travel ban is in place.
“State visits are designed for both the host, and the head of state who is being hosted, to celebrate and entrench the friendships and shared values between their respective countries.
“A state visit from the current president of the United States could not possibly occur in the best traditions of the enterprise while a cruel and divisive policy which discriminates against citizens of the host nation is in place.
“I hope President Trump immediately reconsiders his Muslim ban.”
Mr Corbyn said Mr Trump’s state visit should be called off until he cancels the 90-day ban on citizens from Syria, Iraq, Iran, Sudan, Libya, Somalia or Yemen entering the US.
He said: “Is it really right to endorse somebody who has used this awful misogynistic language throughout the election campaign, awful attacks on Muslims, and then of course this absurd idea of building a wall between themselves and their nearest neighbour?”
He added: “I think we should make it very clear we are extremely upset about it, and I think it would be totally wrong for him to be coming here while that situation is going on. I think he has to be challenged on this.”
Labour MP Dan Jarvis said it was “very likely” there would be an urgent question in the House of Commons on Monday to discuss the travel ban.
Demonstrators are planning to protest against the policy outside Downing Street and across the country on Monday evening.
Tim Farron, the Lib Dem leader, also called for the visit to be put on hold until the ban came to an end.
He said: “Otherwise Theresa May would be placing the Queen in an impossible position of welcoming a man who is banning British citizens purely on grounds of their faith.”
Diplomats have already begun preparations for a visit designed to reinvigorate the transatlantic special relationship.
Discussions are underway about the president playing a round of golf on the private nine-hole course at Balmoral while the Queen looks on.
The Duke and Duchess of Cambridge are also set to be involved as the royal family rolls out the red carpet for the US President and his First Lady.
Mr Trump’s team want to create a photograph opportunity to rival the famous images of President Ronald Reagan horse riding with the Queen at Windsor Castle when he visited in the 1982.
Other plans include a personal tour of the Churchill War Rooms from Boris Johnson, the Foreign Secretary, and dinner at Blenheim Palace, where Sir Winston was born.
If the Queen were to agree it would make a break in protocol because the Queen traditionally goes on holiday to her Scottish castle in August.
But Alistair Burt MP, a former Tory Foreign Office minister, said the “optics” of President Trump’s visit were “very bad” and there should be a “joint decision” to delay the visit.
US officials “should help the UK to try and find a reason for why this visit should not go ahead in the short term”.
Parliament has already debated Mr Trump once, after he first floated the idea of banning Muslims from America.
He was described as a “buffoon, demagogue and wazzock” in the debate a year ago after a similar petition was signed by more than half a million people.
The current petition had only 60 signatures on Saturday afternoon, but had smashed the 100,000 mark by noon on Sunday.
Buckingham Palace refused to comment.