2018 is shaping up to be a year for notable 70th birthday celebrations. Not only will July mark the founding of the NHS by the post-war Labour government, but last week saw another anniversary.

Seventy years ago the MV Empire Windrush docked at Tilbury Docks, commencing a wave of immigration from the Caribbean. Tens of thousands of desperately needed workers had been invited from distant lands by the government to fill essential job vacancies, especially as nurses in our fledgling NHS. There was an implicit assumption behind this: immigration is a positive force.

Roll on seventy years and the whole world seems to be hell-bent on forgetting that lesson. In the USA, a land where anyone not Native American is necessarily descended from immigrants, we have witnessed extraordinary scenes. Thousands of children have been forcibly taken from their parents and imprisoned in wire cages. Their crime? Being the offspring of economic or political migrants, many of whom are seeking to claim asylum as refugees, as is their legal right under the 1951 UN Refugee Convention.

In Hungary, Poland and now Italy, politicians are playing the anti-immigrant card for all it is worth. And every month seems to bring about another tragedy in the Mediterranean as desperate migrants – many fleeing war and terrible poverty unimaginable in the West – drown when their flimsy, overcrowded ships sink.

Of course, it would be nice to say the UK is above mistreating immigrants. But no, recent months have uncovered a tawdry tale of what amounts to officially sanctioned cruelty.

Back when she was Home Secretary, Theresa May instituted a covert policy of creating a “hostile environment” for all immigrants, regardless of how long they have lived in the UK or their contribution to our nation. As a result, thousands of members of the Windrush generation have found themselves imprisoned, deported, or denied essential medical treatment despite working and paying taxes in this country all their lives.

The aim was to appear tough on immigration through enforcing deportation targets and quotas. The result was to deny many British citizens their basic rights by insisting on absurdly demanding proof of residence going back decades.

The official narrative from the government is to pretend the whole thing is a terrible shock to them. This is bunkum. Indeed, rather than take responsibility for their policies, they have expended great effort in covering up the chain of events that led to the mess. Above all, they have sought to pretend that Theresa May as Home Secretary had nothing to do with it.

Hence a concerted effort by Conservative MPs and their DUP partners to prevent emails, text messages, correspondence and minutes of meetings from being placed in the public domain. Even now, months since the scandal broke, no figures have been released by the Home Office revealing the number affected.

With Brexit looming we really need to get our heads round immigration. Unless we do, it is highly likely the final Brexit deal could collapse into a ‘no deal’. For anyone with a grasp of how the economy works, that is a frightening prospect. Already strawberry and other soft fruit farmers are warning of potential shortages this summer as they struggle to find enough workers to pick fruit. Huge numbers of industries rely on guest workers from all over the world, including public services like the NHS.

There are other compelling reasons to abandon the government’s “hostile environment” approach. For one thing it flies in the face of common sense. An incalculable number of British people are descended from migrants – and that is especially true of York, where the Walmgate area, for example, was crammed with Irish in the early years of the last century.

The reality is that migrants have always enriched our national life, going through a classic cycle of arrival, establishing themselves, then being absorbed into the culture and adding their own special contribution. Personally, I love the multicultural aspects of modern Britain. If we’re going to put anything in a cage, let’s make it intolerance and ignorant, uncaring attitudes that serve no one but cynical politicians seeking to divide us for their own ends.