Migration is a part of today’s world. We can’t just shut the borders, whatever the Leave campaign tells you

Migration is a worldwide phenomenon that requires a worldwide solution, not a retreat into fairytale delusions

Nigel Farage has put immigration at the heart of his Leave campaigning (EPA)

And so our membership of one of the world’s greatest multinational partnerships has been reduced to a single-issue protest over immigration. The dog whistle has been dispensed with. Now, with less than a week to go, those who wish us to leave the European Union have plugged their rhetoric into a speaker that emits a continuous low but all too audible hum.

An imagined tidal wave of immigrant bogeymen – from Poles to Romanians, Turks to Syrians – is now the backdrop to the big vote. Polls indicate this crude xenophobia is having its desired effect.

The laser-like focus on immigration has left the Remain side struggling to counter. But with World Refugee Day on June 20th and the referendum just days later, we must call out these tactics for what they are, and get real about immigration in the modern world.

The hostility towards foreigners being espoused by some in the Leave campaign sends a message that we think Britain – like a latter-day King Canute – can hold back the waves of migration sweeping the world; that if we pull up the drawbridge and stick our fingers in our ears, it will all just go away.

That couldn’t be more wrong. International migration is a permanent feature of a globalised and interconnected world that tolerates extreme inequalities of wealth and opportunity. And if we look across the whole world – not just Europe – it’s quite clear that immigration and economic vitality go hand-in-hand. People flock towards centres of opportunity and this fuels growth and job creation. The phenomena are inseparable, especially in countries (like ours) where natural population change is either static or falling.

According to the UN, there were 244 million international migrants in 2015, up from 153 million in 1990 (a 60 per cent increase), plus another 60 million forcibly displaced people.

What’s more, there are 49 countries with a higher proportion of immigrants in their populations than the UK, many of which have (or recently have had) thriving economies. In some of the Gulf States, for instance, immigrants form over two thirds of the total population.

It’s notable that the UK has the tenth highest number of its own citizens living abroad worldwide – nearly 5 million – many of whom left our shores to seek better opportunities.

So migration is simply a feature of our world as it is now. It’s the “new normal”. Fortifying our borders in a misguided attempt to protect “our wealth” without doing anything to redress the global inequalities that are at the root of the problem will solve nothing.

Rather than seeking to withdraw from the world, Britain should be playing a full and active part in creating global prosperity so that people don’t feel so straightjacketed by circumstances that they need to escape. The refugee crisis is a case in point. Britain has done precious little to assist, while throwing up obstacles to a fair distribution of refugees across Europe.

The relatively small numbers of refugees that do make it here face the greatest opprobrium of all migrants: while being depicted as being mostly undeserving of our charity, their right to work is often denied while they are nevertheless castigated as a burden.

Taking an active role in the economies of host countries allows refugees to keep their morale high and develop their productive skills and capacities, allowing them to play a key part in post-conflict reconstruction if and when they repatriate.

In this, Britain and Europe could learn something from the experience of Uganda, which (unlike many of its neighbours) has given refugees entering its territory the right to work.

This has not only assisted integration, but also, in the case of Rwandans fleeing the 1994 genocide, enabled them to return home and rebuild their nation, creating one of Africa’s greater success stories.

The experience of Uganda also shows that, far from taking jobs from citizens, refugees often bring with them an entrepreneurial mindset that in fact creates wealth and jobs.

The mixing up of a Brexit decision with immigration issues will come back to haunt us. We’re in danger of putting so much in jeopardy on the basis of the single issue of migration – a worldwide phenomenon that requires a worldwide solution, not a retreat into fairytale delusions that represent a denial of the real world.

Professor Henrietta Moore is director of the UCL Institute for Global Prosperity. She writes in a personal capacity

The EU referendum debate has so far been characterised by bias, distortion and exaggeration. So until 23 June we we’re running a series of question and answer features that explain the most important issues in a detailed, dispassionate way to help inform your decision.

What is Brexit and why are we having an EU referendum?

Does the UK need to take more control of its sovereignty?

Could the UK media swing the EU referendum one way or another?

Will the UK benefit from being released from EU laws?

Will we gain or lose rights by leaving the European Union?

Will Brexit mean that Europeans have to leave the UK?

Will leaving the EU lead to the break-up of the UK?

What will happen to immigration if there's Brexit?

Will Brexit make the UK more or less safe?

Will the UK benefit from being released from EU laws?

Will leaving the EU save taxpayers money and mean more money for the NHS?

What will Brexit mean for British tourists booking holidays in the EU?

Will Brexit help or damage the environment?

Will Brexit mean that Europeans have to leave the UK?

What will Brexit mean for British expats in Europe?