When the foreign secretary, Philip Hammond, talked of the threat to the UK from “marauding migrants” at Calais last week, I decided to review the stories of the hundreds of foreign-born workers I have met in more than a decade of writing about their lives in the UK: those working for the mainstream economy, albeit hidden in the shadows of its long subcontracted supply chains, whether in food production, construction, care work, cleaning or catering.

What becomes immediately clear is the deep dishonesty at the heart of much of the rhetoric on this issue. The right claims to be tough on immigration, but it is the opposite of tough on the causes of immigration. It promotes a business model that depends on a constant churn of workers to carry out jobs that are underpaid and insecure at best, and all too often dirty, dangerous, and degrading. It requires not just immigration, but immigration without end, since only the newly arrived, the desperate and the vulnerable will tolerate the conditions that have been created, as the roll call of migrant workers I have met, with its constantly changing nationalities, shows.

In 2002, there were the factory workers living on the south coast putting in long shifts as chicken processors for high street names in Sussex. They were a mix of refugees who had fled war in Kosovo and Afghanistan, and economic migrants here legally from the poorer parts of the European Union including Spain – and illegally, from countries beyond the EU’s borders, such as Ukraine and Russia.

Lithuanian migrants trafficked to UK egg farms sue 'worst gangmaster ever' Read more

By 2004, I was meeting frightened debt-bonded South African migrants, with legitimate Commonwealth working visas, living in squalor while packing pears for a Tesco supplier near Spalding; they got out soon after.

Then there were the cheerful, educated Iraqi Kurds in illegal employment, processing supermarket vegetable orders near Boston while living in Peterborough and waiting for their asylum cases to be heard.

After them I found large numbers of recent Portuguese migrants intimidated and paid less than the minimum wage in and around the Norfolk town of Thetford – birthplace of Tom Paine, the 18th century radical and revolutionary proponent of the Rights of Man.

They were accompanied in the mid-2000s by Brazilian migrants pretending to be Portuguese in nearby Brandon, and, surreally, their Portuguese friends who pretended to be Brazilians pretending to be Portuguese, because their gangmasters actually preferred taking on people who were working illegally and could therefore be exploited more thoroughly.

In Herefordshire, and going back to Thetford a few years on, I met lots of Polish workers. They had replaced the Portuguese in the fields and the packhouses as the former group settled and moved up into better lives. The Poles had worked illegally at first in the worst jobs and then, after Poland’s accession to the EU, moved through agencies into long-term factory positions in a large meat plant, where they had joined the union. They were being made redundant along with English colleagues as cheaper casual agency staff made up of newer arrivals were brought, in and part of the company was relocated to Cornwall to cut costs.

In the past few years the casual migrant workers I have met in the agriculture, manufacturing and service sectors, such as car washing, have mostly been from Lithuania or Latvia, and the poorer areas of the former Soviet bloc.

Office for National Statistics figures released last week show that almost three-quarters of employment growth in the past year was accounted for by non-UK citizens, with more than 250,000 new jobs going to EU and other migrants, suggesting the pattern continues.

The zero-hours agency habits pioneered in the food and agriculture sector have spread across the economy

Last week we reported on a group of 30 or so Lithuanian workers who were being severely abused and exploited while working as chicken catchers, rounding up hens on the UK’s largest poultry farms. They were part of the supply chain producing eggs for most of the UK’s largest retailers. The conditions – typically weeks of more than 120 hours, continuously on the move, charged for squalid tied housing, with allegations of pay withheld, threats of violence and actual assault – were intolerable.

Whereas field work and packing and processing were once given to local workers with reasonable family-friendly hours and the chance to top up pay with voluntary overtime at weekends, now it is 24/7 rolling 12-hour shifts confirmed only at short notice, theoretically for the national minimum wage.

The zero-hours agency habits pioneered in the food and agriculture sector have spread across the economy. In the south-east, Ukrainian and Chinese workers are the predominant nationality on the domestic building sites I have seen, providing cheap hard labour to dig out new underground floors for affluent renovations by hand. We have created jobs that are inhuman, and incompatible with any normal settled existence.

Instead of regulating these sectors properly, taxpayers’ money has been used to augment inadequate pay in the form of tax credits to low-paid UK and EU workers – introduced by Labour – subsidising profitable businesses with corporate welfare. The Conservatives have trumpeted their intention to move from tax credits to a living wage. But enforcement of the national minimum wage, never mind a living wage, has been feeble and inadequate under successive administrations, including theirs.

The government’s migration advisory committee calculated in 2014 that that a business might statistically expect a visit from one of just 142 national minimum wage inspectors once every 250 years. The government has increased the team this year to 230, hardly enough to make employers quake. A sustained assault on union rights has seen the steep decline of recognition and collective bargaining that might take on the asymmetries of power in the work place. The Conservatives have announced yet more anti-union legislation.

Equally dishonest is the myth that migration can be controlled, if only we had sharper razor wire, or more border dogs, or more deportations of illegal immigrants. As the Ministry of Defence’s strategic trends programme makes clear, today’s large-scale migrations are a historic force, just as those from rural areas to emerging cities were in the industrial revolution. They will increase in coming years as the global population grows, as the tectonic plates of superpower relations continue to shift, as the world’s resources come under increasing pressure from our patterns of consumption – and as more and more people flee war, climate change and poverty. Our failure to curb emissions will bring the victims of our footprint to our door.

We are all interdependent. We have enjoyed the growth globalisation has brought to advanced economies, but we cannot escape its flip side. The Dover-Calais route, with its queues of holiday-makers and freight lorries is the perfect symbol of the contradictions inherent in the anti-immigration view. It wants the free movement of goods and capital, the ability for its own to come and go as they please, but it wants fortress Britain for everyone else.

There has been a lack of honesty on the left too. The flexible workforce was a mantra of the Labour years. While insisting that migration has been of overall benefit to the economy, Labour was slow to acknowledge that the benefit has flowed mostly to capital and the rich, and far too slow to articulate that at the microeconomic level some British groups have clearly have lost out. But to imagine now that the solution to these new global realities can be found by tacking to the right, or by turning back to the answers of the 1970s pre-globalisation is deluded.

Tory tilting at windmills comes as no surprise. But there are expectations of Labour and rightly so, for the Labour movement itself was born of the struggle to address the structural inequalities of the economy of the late 19th and early 20th centuries. If it cannot address the losses felt by both local and migrating communities today, I’m not sure I understand the point of it anymore.