British politicians have discussed banning Donald Trump from entering the UK, but agree the move would go against free speech.

Most members of parliament said on Monday that Trump should be allowed into Britain where his "crazy" and "offensive" views could be challenged.

"I want to see Donald Trump come to this country ... I want him to get a sense of the fury and the frustration with his xenophobic remarks," said Gavin Robinson, a legislator from Northern Ireland's Democratic Unionist Party.

Trump caused outrage last month with his comments that Muslims should be banned from entering the United States. He spoke after 14 people died in a shooting spree in California, allegedly committed by two Muslims whom the FBI said had been radicalised.

MPs also said the ban would give Trump more publicity or that it was not for Britain to get involved in US affairs.

The debate was prompted by a petition with nearly 574,000 signatures that urged the MPs to keep the controversial US presidential candidate out of the country.

There was no parliamentary motion or vote after Monday evening's debate, and only interior minister Theresa May can issue an order banning entry.

The UK has previously denied entry for religious leaders accused of promoting "extremist" beliefs and politicians, such as Dutch MP Geert Wilders, and those who have faced charges of Islamophobia.

'Divisive, stupid, and wrong'

Responding to a question in parliament last month, David Cameron, the British prime minister, called Trump's comments during his campaign "divisive, stupid, and wrong", but said the Republican frontrunner should not be banned.

"I think if he came to our country, he would unite us all against him," Cameron said.

The debate came as a left-wing activist group, Rise Scotland, demonstrated at properties owned by Trump in Scotland in solidarity with minority groups in the US.

"We aim today to disrupt, however briefly, Trump's ability to generate profit in Scotland that will then be spent on his campaign of racist demonisation and scapegoating in the US," the group said in a statement on its website.

Earlier, Trump demanded the construction of a Mexican-funded wall on the US-Mexico border to keep migrants out of the US.

His views have attracted criticism domestically and internationally, as well as from within his own party. Yet, Trump holds a double-digit lead in the polls over his next closest opponent in the Republican nomination race.