Thirty-nine people were found dead in the back of a refrigerated lorry on an industrial estate in Essex last week. Much remains to be determined in this specific case, but we know this at least: borders kill people.

In 2000, 58 people were found dead in the back of a refrigerated lorry at Dover. In 2012, Jose Matada fell from a plane flying in to the UK from Angola over East Sheen. In 2015, another man fell from a plane, this time over Richmond. In 2019, a man fell from a Kenya Airways flight into the garden of a residential property in Clapham.

It is just over four years since Kurdish Syrian toddler Alan Kurdi washed up drowned on a beach near Bodrum in Turkey. Nine people died in or around the Channel Tunnel in the first six months of the same year. Almost 16,500 people have died crossing the Mediterranean to reach Europe since 2015. This summer, an Iraqi man died trying to swim across the English Channel to the UK.

The deaths of the "Essex 39", as they have come to be called, has unsurprisingly led to a renewed focus on borders as physical infrastructure. We have zeroed in on details such as the proportion of containers x-rayed at Zeebrugge port, through which the 39 are believed to have travelled.

But to grasp the full horror of what happened last week, we need to understand that borders aren’t simply fixed in time and space at the outer limits of a territory. They are also legal regimes, covering visas, citizenship and immigration, which all too often exclude everyone who isn’t rich, able or willing to work, or from the global North from lawful status, and hand bosses, landlords and the Home Office and its equivalents enormous power over those who are permitted to come.

People move and always have. Borders are silent on the myriad reasons for this, from human rights abuse, war, climate degradation, and poverty to study, family and love – many of which have been cited by the family and community of the Essex 39. Borders don’t stop people from moving, but they do dictate how safe or perilous a person’s journey will be, how much it will cost them, in all senses of the word, and the kinds of obstacle to a flourishing life a person will face on arrival. Borders are the difference between who has to pay a smuggler and risk a journey in a refrigerated, unventilated lorry like the 39 people who died last week, and who can travel in relative safety with a visa and a plane ticket.

The danger of the border does not end once it has been crossed. Had the "Essex 39" made it to the UK alive, the border would still have established itself in the most intimate reaches of their lives.

Under the hostile environment, a person’s immigration status determines whether they can open a bank account, work, and lawfully rent a property, or whether they must rely on the irregular labour and housing markets for shelter and survival. That legal status sorts people who are able to assert their rights from those forced to live in fear of any interaction with the state. Why else would the Essex police have found it necessary to reassure anyone who comes forward with information about last week’s events that “they will not be deported”? – because over half of police forces have reported victims of crime to the Home Office.

The hostile environment remains more or less untempered following the Windrush scandal, and a mainstay of the government’s stated post-Brexit immigration policy. Knowing this, what exactly did the Prime Minister mean when he declared that these deaths were an “unimaginable tragedy and truly heartbreaking”? What did the Home Secretary, who recently announced the end of free movement with a twinkle in her eye, mean when she claimed to be “shocked and saddened”?

Borders do not simply concern people who are not yet “here”. They continuously regulate the lives of people within a territory, as well as people outside it. This is how Kelemua Mulat came to die after being denied potentially life-saving cancer treatment for weeks after an NHS Trust decided that her treatment was not “immediately necessary” and that she would have to pay. It is how Mustafa Dawood died at his workplace, falling through the roof of a building as he fled an immigration raid in Newport. It is how Joy Gardner was killed by the police and immigration officers during a deportation raid on her London home: shackled, gagged, and wrapped in 13 feet of adhesive tape.

There is no humane border. Stopping borders killing and harming people means abolishing them. That starts with action in the here and now to force divestment from the machinery of immigration enforcement, reducing its reach into people’s lives; and practical solidarity with those who are its targets.

That action could take many forms: it’s supporting and amplifying the struggles of migrant workers and people in immigration detention. It’s accompanying people to appointments to sign at the Home Office or apply for support from the local authority. It’s visiting people in immigration detention. It’s public servants organising to refuse complicity in immigration control. It’s setting up anti-raids groups so that our communities can block or resist immigration raids, as activists from Reclaim the Power did only this week. It’s pressuring the private companies that make immigration enforcement possible, be that G4S, one of many companies involved in immigration enforcement in the UK and globally, or Palantir and Amazon, which provide technical capabilities to US immigration enforcement authorities.