In March, a pregnant woman in her 20s went to the Metropolitan Police to report being kidnapped and raped. She was herself arrested, interrogated on suspicion of illegal entry into the UK, and eventually released pending a decision on her case.

This is Britain under Theresa May’s flagship “hostile environment” policy, of which she laid the foundations as Home Secretary, as far back as 2013. Doctors, social workers and teachers are forced to act as border guards. Every job application and health emergency could end in arrest, detention or summary deportation.

Under the hostile environment, fear and penury are systematically imposed on undocumented migrants, legal EU and non-EU migrants and Britons of colour, in an attempt to make Britain as cruel and unwelcoming as possible to those who do not ”belong” here. Post-Brexit, the hostile environment is spreading, jeopardising even those middle-class European migrants who previously thought themselves safe.

To the most vulnerable migrants in our society, however, fear and isolation have long been conditions of existence. David is a migrant worker from Spain who sleeps rough on a rooftop in North London, and a witness to the hostile environment’s crudest excesses.

“I’ve seen it with my own eyes,” he tells me, stamping his feet against the biting cold as sleet swirls around him through the streets of Camden. “Especially Eastern Europeans, sleeping rough around Charing Cross. [The police] come in the night with a printed list of names and dates of birth. People are here one day and gone the next.”

The sleepers disappearing in the night

For the last 18 months the Home Office has considered rough sleeping an “abuse” of European Economic Area (EEA) citizens’ right of freedom of movement, and sufficient grounds in itself for deportation. Prominent homelessness charities like Thames Reach and St Mungos played along, sharing data on EEA rough sleepers and handing homeless EU citizens into the tender care of the Home Office.

That policy was struck down by the High Court just last week, found to be unlawful and discriminatory. But hundreds, if not thousands, of rough sleepers who would otherwise have been allowed to remain in the UK have already been deported for no crime other than their poverty. And the hostile environment is still working in a host of other, more pernicious ways, beginning far before deportation takes place.

There are two key strands to this policy, cooked up by a body initially dubbed the “Hostile Environment Working Group” and made law in the Immigration Acts of 2014 and 2016. First, force employers, landlords, schools, universities, banks, doctors and local government employees to run their own checks, and hit them with criminal charges if they fail to report anyone they believe to be in the country illegally. Second, strip away welfare support and access to NHS and public services, making Britain so profoundly unwelcoming that people “choose” to leave of their own accord.

For example, since 2014, EEA migrants cannot access housing benefit, and must wait three months to claim jobseekers’ allowance. As David, the rough sleeper from Spain, points out, this is a lifetime on the street: “The people are desperate. They lose the option of working in a legal market, in a clean way… there’s no chance of a mortgage and [accessing support] services is even harder.”

Piecemeal work like handing out club flyers or selling black-market alcohol and cigarettes in the street leaves David with no chance of raising the deposit and month’s rent he would need to get a roof over his head. The foreign-born nationals who make up over half of London’s rough-sleeping population cannot normally access our hostel network, since it is paid for by the housing benefits they are not allowed to claim.

David is lucky if he can end the day with £15 in his pocket to get a bunk in a squalid room shared with ten other men. “We call that a holiday,” he says with a bitter laugh.

Free movement campaigners, on the other hand, call it “the creation of an illegal underclass of foreign, mainly ethnic minority workers and families who are highly vulnerable to exploitation and who have no access to the social and welfare safety net.”

The families slipping under the radar

Life is harder yet for those who arrived here irregularly, from outside the EEA. Nigerian-born Gloria has been in the UK for the better part of two decades on a long-expired visa. As we sit in a poky back room of the friend’s flat where she is currently staying, she explains that her primary school-aged kids were born to a British father and have lived here ever since.

Gloria has the legal right to remain in the UK while her status is being reviewed by the Home Office, but no way to work legally. “My children don’t have child benefits,” she says. “They don’t have anything. I can’t access any public funds, Jobseekers’ allowance, tax credits…”

If they can prove they are truly “destitute”, the mothers of British-born children can theoretically claim a bare minimum of social support. But when they go to social services for help they are met with a barrage of measures intended to drive them back to the countries they fled.

Women are regularly warned their children will be taken into care, threatened with deportation, or otherwise bullied into leaving the country, according to activist group North East London Migrant Action. They are subjected to harsh and invasive means-testing, refused help on flimsy pretexts, and left homeless by austerity-hit councils looking for any excuse not to offer financial aid.

This “gatekeeping” is the hostile environment at its most viciously double-edged. At the same time as blocking vulnerable women and children from accessing support which will keep them from homelessness, it uses their desperate cries for help as a cue to drive them out of the country.

Gloria herself was kicked out of accommodation for destitute mothers by Hackney Council: “They said my children are not in need. But we could have been in the street.” She also despairs over the four-figure cost of citizenship applications for her children. These applications are a money-spinner raking in millions for the Home Office each year, but another back-breaking burden for impoverished migrant mums.

David blames the fact that the government “lets private landlords put rent as high as they want” for driving poor young workers like him into the street. But those able to scrape together a few hundred quid to rent a room do not escape the hostile environment either. Landlords now carry out 10,000 “right to rent” immigration checks on their tenants every day.

Distressingly, 44 per cent of landlords say they are less likely to let to people who “appear to be immigrants”, according to a survey by the Joint Council for the Welfare of Immigrants. A mystery-shopping exercise found 58 per cent turned down applications from a British Black Minority Ethnic tenant. The hostile environment creates a wider environment of hostility, which does not spare those who merely look like they might be migrants.

In turn, this atmosphere of hatred and mistrust fosters Islamophobia, racism, and public support for anti-migrant policies. It’s less a vicious circle than a perpetual-motion machine.

The academics caught in the net

“Monitoring via tenants’ records creates uncertainty, precarity, and continual violence,” US-born academic Sanaz Raji tells me. She herself has been the subject of a prolonged battle over her immigration status, forced to live off the charity of friends and constantly move from home to home, at times paralysed down one side by functional limb weakness. “I didn’t know stress could do that to your body,” she continues, at times choking back tears so as not to disturb the studious hush of Manchester library foyer.

Raji was involved in a drawn-out dispute with her superiors at the University of Leeds over the termination of her PhD. The university said the PhD was terminated because of poor academic progress. Nevertheless, the dispute illustrated the power of the hostile environment. Emails obtained via Freedom of Information Request showed Raji’s superiors at the University of Leeds celebrating the “good news” that “border control” might be throwing her out of the country.

Sanaz sees her maltreatment as part of a wider drive to make academic institutions fall in line with the government. She recalls appealing to fellow academics from EU countries several years ago, and being disappointed with their lack of solidarity: “They said ‘I’m not worried about it, it’s not my issue.’ Now with Brexit it’s been spread out to them as well, and they’re quaking in fear.”

Brexit and the hostile environment

Irregular non-EU migrants suffer the most, but the hostile environment eats through society like a fungus, undermining those who thought themselves safe. Following Brexit, many British people with European and foreign-born spouses have also been hit by hostile environment policies, “tearing families apart” as the Home Office refuses to grant marriage visas on the most arbitrary of pretexts.

If the hostile environment is to be countered, Brexit must be understood not as a rejection of “civilised” or “cosmopolitan” European values by an imaginary white working class, but as a continuation and extension of hardline Tory policies which have long targeted working-class migrants.

In fact, it is migrant-led campaigns which are doing the most to improve conditions for British workers. This year alone, the International Workers of Great Britain union has won a series of victories against Uber, Addison Lee, and other unscrupulous employers.

By highlighting these struggles, campaigners can make it clear who the enemies of the British working class really are. If the UK Border Agency comes for the cleaners today, it will be coming for the lecturers tomorrow.

As in universities, so in schools: the Home Office gets information on 1,500 minors a week from the Department of Education, with the explicit aim of “creat[ing] a hostile environment” in the classroom. Since October this year, doctors and nurses are supposed to demand patients’ passports before treating them, with non-EU migrants and students forced to pay to access many life-saving services.

The New Year will be heralded by checks on 70 million bank accounts, with banks once again being penalised if they fail to screen their customers or turn in the undocumented migrants they find. New post-Brexit proposals could see work permits for most EEA migrants slashed to just two years, in what is being described as “hostile environment 2.0”.

Yet those already here keep struggling on. There is no evidence that the hostile environment even does what it is supposed to do, with no increase in either enforced or voluntary returns since the hostile environment was first rolled out by Theresa May back in 2012.

The policy is touted as a deterrent. But EU nationals – mostly skilled workers fleeing the UK – account for three-quarters of the drop in net migration since Brexit, and far more people are still arriving in the country than leave it every year.

People fleeing war or abject poverty in formerly-colonised countries are not going to stop trying to get to Britain just because they can’t receive cancer treatment or rent a home. They don’t have these things in the Calais wasteland where many are sleeping, after all.

Despite everything the Government is doing to make their lives unbearable, migrants still want to travel here, to live and work, to play their essential part in our society. Sanaz is still fighting her case via the #Justice4Sanaz campaign: David is still curled up on a rooftop somewhere in Camden. All the hostile environment does is make life more violent and fearful for those already in the country.

Some names have been changed to protect interviewees’ identities.