Protesters across UK denounce government plan to halt migrants' Channel crossings
Around 2,000 protesters, many carrying signs reading "no human being is illegal" and bearing trade union logos, marched towards Downing Street, the prime minister's official residence.
Organisers said the demonstration was partly a response to the government's "inhuman" and "illegal" migration bill.
"People in this country are decent and they're willing to open their arms to people who are fleeing terrible circumstances," said the protest's planning officer Mark Daly.
"The government is trying to make these people not only unwelcome but illegal. We cannot classify people as illegal," he said. "It's a racist policy from a racist government".
Other protests took place in Glasgow, Scotland, and the Welsh capital Cardiff.
The Conservative government wants to outlaw asylum claims by all illegal arrivals and transfer them to "safe" third countries, such as Rwanda, in a bid to stop thousands of migrants from crossing the Channel on small boats.
The bill proposes preventing people who have arrived in the country illegally from seeking asylum before they are sent to a third country deemed safe.
Exceptions would be made for unaccompanied minors.
More than 45,000 migrants arrived in the UK last year by crossing the English Channel on small boats.
UNICEF, the UN children's agency, said last week that it was "deeply concerned" about the bill's potential impact on minors. So too has United Nations High Commissioner for Human Rights Volker Turk.
Prime Minister Rishi Sunak told the House of Commons earlier this month that stopping the boats was the "people's priority".
On Saturday, interior minister Suella Braverman was visiting Rwanda to reaffirm her commitment to the government's policy to deport migrants there.
Accompanied by Rwandan Foreign Minister Vincent Biruta, Braverman defended the policy at a news conference.
"I sincerely believe that this world leading partnership between two allies and two friends, the United Kingdom and Rwanda, will lead the way in finding a solution which is both humanitarian and compassionate," she said.
Biruta told journalists: "This will not only help dismantle criminal human smuggling networks, but also save lives".
Braverman has repeatedly insisted the government is within its rights to stop the migrants crossing the Channel, who she said could total 80,000 this year.
When she presented the Illegal Migration Bill to parliament last week however, she attached a note conceding that she could not confirm yet whether the plan respected European human rights law.