London, England - Tens of thousands of people across Britain have protested against Prime Minister Theresa May's decision to formally invite US President Donald Trump to the country.

Protesters at Monday evening's gatherings demanded that the government withdraw its invitation in light of Trump's decision to ban citizens of seven Muslim-majority countries from entering the United States.

The rallies, which were held in every major British city and several smaller towns, drew huge crowds despite being announced less than a day earlier.

May, who met Trump a day before the ban was announced, has refused to rescind the invitation despite strong rebukes from opposition politicians and a parliamentary petition that has so far collected more than 1.5 million signatures.

OPINION: Trump's Muslim ban is a dangerous distraction

The opposition leader, Labour's Jeremy Corbyn, has called May a disgrace and demanded that Trump be banned from the UK until the bar on Muslims entering the US is lifted.

Visitors, refugees and migrants from Libya, Iran, Iraq, Somalia, Sudan, Syria and Yemen, are not allowed to enter the US after Trump issued an executive order banning them.

'Don't come here'

In London, barricades aimed at keeping protesters penned in a square opposite May's residence at Downing Street were quickly made redundant as tens of thousands flocked to the area.

Demonstrators came armed with placards, many containing expletives aimed at Trump and May, and others warning of the historical consequences of tolerating the far right.

"It's fantastic ... look at it, you can't get in or out," school teacher Fraser Miles told Al Jazeera when the crowds were at their peak.

When asked why he had come, Miles said it was to tell the US president to "f*** off".

"Don't come here, we don't want you, we don't want your racist ideology. Go away. That's what everyone is thinking," he said, adding that he wanted to make sure Muslims and immigrants of all backgrounds understood they were welcome in the city.

"I hope they [Muslims] know that we in London don't view followers of any religion as a different group of people ... there's no reasoning for what Donald Trump has done, it's just pure racism."

Rachael Withers, who brought her three-year-old son to the protest, said she wanted to show that May's ties with Trump did not represent British values.

"Our values are about inclusivity. Our whole city exists because of immigration. Without it, London just wouldn't work and the idea of locking people out because of their religion is totally against what Britain is about," she said.

Withers said earlier examples of fascist rule and the lessons of World War II had encouraged her to make a stand against Trump's policies.

I think maybe it's been so long since the Second World War that people have forgotten how dangerous fascism can be Rachael Withers, protester

"I think what would I have done during the war, and now I'm in that situation, I'm going to protest until something changes."

Solidarity

Students Rasha el-Zein and Sultana Yasmin, both Muslims, told Al Jazeera that that they appreciated the show of solidarity.

"There's a lot of fear being a Muslim these days, especially as someone who wears hijab, you feel targeted. But when we're among these [protesters] we don't feel any different," said el-Zain

"It makes me happy ... after Brexit we felt the divide but when we come to a protest like this you feel like there is unity," said Yasmin.

Trump's ban prompted global condemnation and has sparked protests within the US, with activists there gathering at airports across the country to demand that US authorities release detained nationals from the affected countries.

The order signed over the weekend is being challenged in the courts by the American Civil Liberties Union (ACLU).