Dr Tania Mathias is MP for Twickenham.

The most worrying aspect of Donald Trump’s harmful and divisive refugee ban is the impact it will have on the global response to the refugee crisis.

UNHCR, the UN Refugee Agency, estimates that the executive order suspending America’s refugee programme for 120-days could affect 20,000 people. Instead of being given the opportunity to rebuild their lives in the US, these individuals and families will be left struggling to survive in camps and on the borders of conflict zones.

I know something of the hardships experienced by refugees, having worked for the UN Relief and Works Agency as a health officer for Palestinian refugees in the Gaza Strip during the first intifada.

Refugee resettlement programmes offer hope for people who have faced unimaginable horrors fleeing war, persecution and terrorism, and give them the chance to rebuild their lives in peace and safety.

The people the UNHCR refers for resettlement to countries such as the US and Britain are the most vulnerable – survivors of torture, women and girls at risk, disabled people and those needing urgent medical assistance. All resettled refugees, including those going to America, already go through a rigorous security vetting process.

We have a legal and a moral duty to protect refugees. It is why Trump’s order indefinitely banning Syrian refugees and temporarily suspending America’s wider refugee programme, feels like an attack on our shared humanity. It is why I do not believe we can justify a State visit while the ban is in place.

Restricting America’s role in resettlement – in the middle of the worst refugee crisis on record – will have a huge impact on this vital worldwide programme. The US has been a world leader in offering sanctuary to refugees and its funding underpins the entire infrastructure of the global resettlement system.

Nearly 85,000 refugees were welcomed last year through the US Refugee Admissions scheme. Barack Obama committed to resettling 110,000 this year, but Trump’s order has reduced that number by more than half to 50,000.

But it’s not just about the figures. Each one represents a vulnerable person or child in need of protection due to situations beyond their control.

There is no end in sight to the war in Syria, or the long-running conflicts and chronic instability affecting people in many other parts of the world. Britain has a long tradition of protecting those fleeing terror, as was so eloquently said in Parliament by Lord Dubs. More than ever, we need to show that refugees are welcome in Britain, regardless of their religion or country of origin.

One of the charities I have worked with, Refugee Action, provides integration support for refugees resettled in Britain through the Government’s Syrian Vulnerable Persons Resettlement scheme and Gateway, which resettles refugees from different parts of the world.

Just this week, the charity welcomed 15 families from Syria, who will have the opportunity to rebuild their lives here thanks to this scheme. But we can and should do more. In the wake of Trump’s policies, now is the time for our Government to show leadership in responding to this global crisis by increasing its commitment to refugees.