There is an urban legend about boiling frogs, and it goes like this. If you put a frog in a pan of cold water and slowly, slowly turn up the heat, the frog will sit there quite calmly until it boils to death. Creeping cultural change is like that. It’s hard to spot when you’re living inside it. You can stay very still while the mood of a society becomes harder and meaner and uglier by stages, telling yourself that everything is going to be fine as all around you, the water begins to bubble.

This week I had coffee with a friend who has also just come back from a year away – teaching in Spain for her, studying in America for me. For both of us, coming home has been hard. There are some things I missed that simply aren’t there anymore. A particular shade of lipstick at Boots. My favourite zombie show on the BBC. And most of all, a sense of basic tolerance, however pretended-at, a feeling that there are some ways of talking in public about people who are not white, or not British, or in any way “other2, which are the province of far-right hate groups, the Duke of Edinburgh and no one else.

“Is it me,” said my friend, “Or is it just...okay to say things that are violently racist now? Has that always been okay, and I just didn’t notice till now?”

No, it hasn’t always been okay, and in fact it’s still not okay – but it is a normal part of the public conversation, in a way it wasn’t, even a year ago. Coming back feels like being plunged into that pan of boiling water, struggling and wondering why on earth everyone else is so calm. It’s not that Britain wasn’t a racist, parochial place before. But the xenophobic, Islamophobic and, most obviously, the anti-immigrant rhetoric has ramped up everywhere.

I noticed it from the moment I picked up the free newspapers they hand out on the plane home – and not just the Daily Mail, which is finally free to be as fascist today as it was in 1935 when it rooted all-out for Hitler and the blackshirts. The other free paper, the Independent, was just as concerned that day with the seemingly unstoppable “tide” of migrants arriving from Calais, many of them from- shock, horror, surely not – Africa (in fact, over half of migrants to Europe come from just two Middle Eastern countries).

By the time we touched down I realised how badly all of us were fooled in May. We made the mistake, all of us, of thinking that UKIP, with 12.6 per cent of the vote share and just one MP, did not win the general election. But the rhetoric of the racist, xenophobic fringe has been adopted by the political mainstream in a way that is no less upsetting for being entirely predictable.

The ultimate victory of fringe groups is not to enter the administration, but to change its direction, and Ukip has done this with aplomb, playing into a broader, well-orchestrated European meltdown over migration. Every paper has led with headlines about the supposed “immigrant crisis”. The prime minister describes migrants to Europe as a “swarm”, and the foreign secretary goes further, warning the people of Britain that the thousands of desperate people drowning in the Mediterranean are “marauding” foreigners who must be prevented from coming here because they will threaten our “standard of living” and our “way of life”.

As the bodies stack up in Calais and the death toll mounts in the Mediterranean, with two thousand migrants drowning this summer alone, ministers are not softening their language. On the contrary: they are doubling down. Fortress Europe must protect its borders from the “influx”, the “tide”, the “flood”. Although new arrivals from nations suffering war, tyranny and climate change made up just 0.027 per cent of Europe’s population last year, it simply cannot be allowed to continue, because… because…

Because what Europe needs now, more than anything else, is a common threat.

The behaviour of the British and wider European elite towards migrants is not simple inhumanity. It is strategic inhumanity. It is weaponised inhumanity designed to convince populations fracturing under hammer-blows of austerity and economic chaos that the enemy is out there, that there is an “us” that must be protected from “them”. There is a reason why David Cameron’s precise suggestion as to how to deal with the desperate human beings coming across the channel is “more dogs and fences”. There is a reason that Angela Merkel’s response, in June, to a demonstration where the bodies of drowned migrants were buried on the front lawn of the Bundestag was stony silence. All of this has happened before. All of this, in fact, is precisely what the European Union was established to prevent.

Fascism happens when a culture fracturing along social lines is encouraged to unite against a perceived external threat. It’s the terrifying “not us” that gives the false impression that there is an “us” to defend.

Living standards have certainly gone down across the eurozone, but that has very little to do with immigration. The chosen minority must summon the fears of every social class at once. That’s why migrants, the bogeyman of choice, are presented as a paradox, just as the Jews were in the 1930s.

Nobody can quite decide whether migrants are a problem because they work so hard that they’re taking all the jobs (the biggest fear of a working class pummelled by unemployment and falling wages) or because they’re too lazy to work so they’re taking all the benefit money (the biggest fear of a middle class suffering with rising rents and cuts to social services);

It cannot be both at once, and in fact it isn’t – but it’s important that the paradox is maintained nonetheless. That’s why the Migration Advisory Council is imposing new, stricter controls on “skilled migrants” entering the country even as it cracks down on an already miserly state support system for asylum seekers.

I don’t know at what point in the past decade the word “asylum seeker” became synonymous with “criminal” in popular conversation, but on that day, the continent of Europe became a meaner, cheaper place.

Human decency, however, has been factored out of the equation – on purpose. Britain and the rest of Europe have deliberately been whipped up into a state of panic over migration, and when people are panicking, they don’t really listen to reason. No amount of reassuring statistics – for instance, that the number of refugees in Britain is not only low, but falling – is going to help when you have the Daily Mail drawing cartoons peopled with racist caricatures where drowned “illegals” are trying to jump the fence into heaven ahead of recently-deceased national treasures and a culture where this is considered publishable in the daily news. This is a debate that tore loose from the facts a long time ago.

So perhaps we should take a different approach. Perhaps those of us lucky enough to be European citizens should take a deep breath and realise that maybe, just maybe, our feelings might not be the most important thing here. That maybe if thousands of people are desperate enough to risk death to come to our shores, whether or not we’re entirely comfortable having them move to our area should not be the deciding factor in policymaking.

The liberal press is as guilty of this as anyone. Notionally more compassionate news outlets take care to remind us that immigrants actually “enrich” our culture and bring economic benefits. The fact that this is entirely true does not make it any less of an offensive argument. Migrants do not come to the west from war-torn Syria, Eritrea, Afghanistan or any other nation that has been colonised and occupied and then bombed and plundered for resources over centuries of imperial and post-imperial exploitation chiefly to enrich the lives of westerners and liven up our god-awful cuisine with some actual flavour. They come out of fear for their lives. They come for asylum and security and opportunity, and they are perfectly entitled to do so, if not by the law of the land then by the principles of justice and human decency.

The greatest threat to our “way of life” is not migration. Migration does change society, although far less so than, for example, technology, economic austerity, escalating inequality, globalisation or climate change. But the greatest threat to our “way of life”, if there has ever been such a thing on this vast and varied continent, is not that someday you or I might be sitting on a bus and hear someone speaking Pashto or Tigrinya. The threat is that we will swallow the public narrative that immigrants, people from non-European countries are less human than the rest of us, that they think and feel less, that they matter less. Europeans are quite capable of sitting calmly in the bubbling water of cultural bigotry until it boils away every shred of compassion we have left. That’s the real threat to our “way of life”.