Donald Trump’s “cruel” ban on people born in certain Muslim-majority countries from entering the US will prevent a British Conservative MP from visiting his children, he has revealed.

Nadhim Zahawi, a British citizen who is now banned from entering the US simply because he was born in Iraq, said the “hugely discriminatory” ban was “demeaning” and “sad”.

He revealed that the ban means he now cannot visit his sons who are studying at Princeton University in the US state of New Jersey, who he previously saw “quite a bit”.

Donald Trump announces a ban on refugees and all visitors from Muslim-majority countries

Last year Mr Zahawi travelled to Princeton to care for one of his children who he said had a “life-threatening illness”. He said this would now be impossible under Mr Trump’s new anti-Muslim laws.

The first day of the discriminatory ban has been marked by reports of refugees being turned away at US airports, including people who worked as translators for the US military fighting against Isis.

Theresa May was criticised last night for refusing to condemn the policy, despite British citizens being affected. In the early hours of this morning Downing Street rushed out a U-turn statement saying that she did in fact oppose it, although she has yet to personally criticise it.

The row came just 24 hours after the Prime Minister stood side by side with Mr Trump and hailed a new era of cooperation with the US regime.

Mr Zahawi said that Britain should not turn a blind eye to the policy, which he predicted would fuel support for Isis in Iraq and other countries affected by it.

“I don’t think we should look away when President Trump makes a mistake,” the MP told the BBC’s The Andrew Marr Show on Sunday.

“I think as his closest allies, Theresa May made it very clear when she talked about us going after the ideology of Daesh, not just on the battlefield. This plays into their ideology: it is counterproductive.”

Speaking of his own personal circumstances, he added: “Our two sons are at Princeton University, so we need to travel to America quite a bit.

“I don’t think I’ve felt discriminated against probably since little school, as a boy from Iraq of Kurdish origin, when young kids were very cruel. For the first time in my life since then, last night I felt discriminated against. It’s demeaning, it’s sad.

“One of my sons had a life-threatening illness last year, and spent time in a hospital in Princeton. He had wonderful healthcare in Princeton University hospital, but we couldn’t have travelled if we were going through the same thing now.

Protesters gather to denounce President Donald Trump’s executive order that bans certain immigration, at Dallas-Fort Worth International Airport in Dallas, Texas (G. Morty Ortega/Getty) (G. Morty Ortega/Getty Images)

“There are many other human stories – the community in the UK. There are hundreds of thousands of people who were born in Iraq who are now British citizens. I always thought we were equal.

May refuses to condemn Muslim ban

“I’m proud Stratford-upon-Avon, 98 per cent white, voted in Nadhim Zahawi, the son of immigrants, an immigrant to this country, as a member of parliament. I hope he’ll reconsider this.”

Labour’s Harriet Harman, speaking on the same programme, said Ms May had suggested Mr Trump’s ban was “nothing to do with us”. “It is to do with us. I understand she has to be careful but she also has to be strong. I’m very disappointed in the Prime Minister.”

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Labour leader Jeremy Corbyn said: “President Trump's executive order against refugees and Muslims should shock and appal us all.

“Theresa May should have stood up for Britain and our values by condemning his actions. It should sadden our country that she chose not to.