Boris Johnson defended Donald Trump as the UK’s “friend and partner” as the row over the US travel ban from majority-Muslim countries deepened and Theresa May faced accusations that she was tipped off in advance about its introduction.

Amid angry scenes in the Commons, the Foreign Secretary said it was wrong to “demonise” Mr Trump for introducing the controversial ban, which has prompted widespread protests and condemnation from other world leaders.

Mr Johnson also refused to answer when asked three times if the US President told the Prime Minister that it was due to be introduced when they met last Friday, and whether she had made any criticism.

Mr Johnson ducked the question on each occasion, insisting he would not reveal the content of the “confidential conversations” in the White House.

He also refused to say whether Britain had raised any concerns before last weekend, given that Mr Trump had promised a travel ban on Muslims before he was elected.

While Mr Johnson told the House that he found the notion of discrimination based on nationality “divisive and wrong”, MPs from all parties lined up to criticise him and the Prime Minister for failing to speak out more strongly against the ban – as other world leaders have.

Veteran Labour MP Dennis Skinner compared Donald Trump to the fascism of Hitler and Mussolini, while another Labour MP, Mike Gapes, branded the Prime Minister “Theresa the Appeaser”. Another warned local schoolchildren had been refused permission to travel to the US.

But Mr Johnson replied: “I think we have got the balance just about right. It’s very, very difficult.

“We have had to be clear with our American friends and partners – but we have also had to ensure important protections for duals and for UK citizens.”

He criticised Labour MPs for “pointlessly demonising” the Trump administration, saying that their approach would put the rights of British passport-holders in danger.

On another occasion, Mr Johnson tried to reassure MPs by saying of Mr Trump: “His bark is worse than his bite.”

He insisted the planned state visit would go ahead as planned this summer, although a proposal for the President to speak to Parliament may be scrapped.

He said: “To the best of my knowledge, both Nicolae Ceausescu and Robert Mugabe have been entertained by Her Majesty the Queen, and I think most members of the House would concede that it is our duty and the right thing to do to put in preparations now for receiving our friend, our partner, and the leader of the oldest, great democracy and the most important ally we have.”

The Commons clashes came as demonstrators started to gather nearby in Downing Street – and after the petition demanding the state visit be cancelled soared close to 1.5 million signatures.

Earlier in the day, the Prime Minister rejected any calls to suspend the state visit, saying she was “very happy” to extend an invitation to the President and had no plans to rescind it.

Worldwide protests followed Mr Trump’s signing of an executive order, which halted the US refugee programme for 120 days and indefinitely banned all Syrian refugees.

It suspended the entry of all nationals from seven majority-Muslim countries – Iraq, Iran, Yemen, Sudan, Somalia, Libya and Syria – on national security grounds, the White House said.

The claim – by Channel 4 News – that Ms May was told some sort of travel ban was coming is hugely damaging, after her initial refusal to criticise the announcement on Saturday.

But, asked if it was correct, Mr Johnson told MPs: “I don’t comment on confidential conversations between the Prime Minister and the US President.

“As soon as we had a full understanding of the measures that they have brought in, we decided to intercede to get the protections that we needed.”

The Foreign Secretary also rejected some MPs’ comparisons to Hitler, saying: “I do find it distasteful to make comparisons between the elected leader of a great democracy and 1930s tyrants.”

Earlier, Mr Johnson attempted to clear up confusion about the status of dual nationals by insisting the travel ban would not affect any British passport-holder.

The US embassy in London had confirmed the executive order would make “no difference” – despite posting advice suggesting otherwise. This advice was later withdrawn.

The Foreign Secretary said: “We have received assurances from the US embassy that this executive order will make no difference to any British passport-holder, irrespective of their country of birth or whether they hold another passport."

He added: “This is not our policy, nor is it a measure that this Government would consider.

“I have already made clear our anxiety about measures that discriminate on grounds of nationality in ways that are divisive and wrong.”

However, Mr Johnson said British dual nationals had been granted an “exemption” – despite No 10 stating all dual nationals, from any country, would not be affected.

It appeared that only Canada, Australia and New Zealand – traditional America’s closest allies for information-sharing – had been given the same exemption.

Jeremy Corbyn stepped up his efforts to get the state visit invitation withdrawn, vowing to oppose “all those who fan the flames of fear at home and abroad”.

In a letter to Ms May, the Labour leader wrote: “Donald Trump should not be welcomed on a state visit to this country while he continues to propagate his anti-women, anti-Muslim and anti-Mexican policies.