Hoppers Way in Singleton, Kent, is a quiet suburban cul-de-sac of red-brick detached houses, each with its own garage and driveway. Parked outside No 8, there is often a large white-and-grey camper van – a luxury Swift Kon-tiki 679 model, with a double bed in the back and another over the cab. Singleton is a suburb of Ashford, the last big town on the M20 as it approaches the Channel Tunnel entrance at Folkestone and a stopping point for Eurostar train services between London and the Continent. That makes it a convenient location for the rental business run by Teresa and Stephen Tyrer, who hire out the motorhome for £1,000 a week to people wishing to travel to Europe.

In early September, the Kon-tiki was in the possession of Paul Coles, 50, and his 22-year-old daughter, Joanne, from near Matlock in Derbyshire, at the southern end of the Peak District. That is about as far from the sea as you can get in England. The Coleses often travel abroad: Joanne is an accomplished motorcycle racer and competes at international meetings. On this occasion, they were attending a competition in Andorra, a principality on the French-Spanish border.

Joanne’s team won gold at the trials, and she and her father returned to the UK on 15 September. During the 1,200-kilometre drive back to Kent, they would have crossed two international borders. The first was on leaving Andorra for France. Andorra is not part of the European Union; it is a tax haven that charges non-citizens €400,000 per household if they want to take up residency there. But for temporary visitors with EU passports, the state is unofficially part of the Schengen Area, the zone of free movement that covers most of the European Union, though not Britain.

The second border was at Coquelles, just outside Calais in northern France, where drivers queue up to put their vehicles on trains that will take them through the tunnel. Since 1994, British passport control has been here, inside French territory (in return, the French get to place their own controls at Folkestone). The arrangement, which is known as “juxtaposed controls” and has since been widened to cover cross-Channel routes elsewhere in Britain, France and Belgium, was a response to fears that better transport links and closer European integration would bring crime, disease and unwanted guests. It is part of a larger system designed to ensure that the inhabitants of Kent suburbs and Derbyshire villages can enjoy the benefits of free movement while being shielded from its consequences.

To some extent, it works: Home Office figures show that between April 2013 and April 2014, 18,000 people – about 50 a day – were stopped at these border controls on the European continent because they did not have the correct documents to enter the UK.

At around 1pm, the Coles family pulled up to the driveway of 8 Hoppers Way and began unloading the camper van. As Paul Coles recalls, he was round the back of the Kon-tiki, sorting out his belongings, when he looked down “and saw these two white eyes staring at me”. A young black man pulled himself up from underneath the motorhome, stood in front of Coles and started to shake and cry. Coles, after he had recovered from the shock, gave him a sandwich and a banana.

The police were called; they searched the man, took notes, and then drove him away in a patrol car. A terse official statement issued later said merely that the man was 18 and from Sudan, and had been handed over to the Home Office’s immigration enforcement department. The Coleses were left to wonder how he had managed to cling to the underside of the vehicle, and for how long.

That young man was one of many who have arrived in Britain in similar circumstances. There was the 16-year-old boy found underneath a school coach as it made its return to Ilford, in Essex, after an outing to France. There was the man who squeezed behind the driver’s seat of a 59-year-old woman’s Fiat Panda, only to jump up as she arrived in Dover, shouting: “I’m an orphan.” And there were scores of others: mostly young men, mostly from Africa and the Middle East, who were found hiding in cars and lorries that crossed the Channel to Britain.

Who are these people, and why do they take such risks? For the past year, I have been researching the journeys taken through Europe by clandestine migrants, and examining the reasons they take them. This autumn, I set out to follow one typical route, tracing it back from London to the shores of the Mediterranean.

About a week before the Coleses made their surprise discovery in Kent, I went to a hotel in south London to visit Samuel, a gentle-voiced man in his early thirties who came from the city of Debarwa, Eritrea, in the Horn of Africa. I had first met him in August when he was still on the French side of the Channel. Samuel told me that a few weeks after this, in late August, he had walked to a lorry park a few miles outside Calais, near the approach road to the Channel Tunnel. In the darkness, as the drivers slept, he found a suitable vehicle. It was a large container lorry, with three pairs of wheels at each end and a detachable cab; the kind you see everywhere on Europe’s roads. They are like the red blood cells of our motorways, carrying goods that keep our high-street shops full, our restaurants cooking and our building sites building. They are also popular with stowaways, and contain several places where a person can be concealed.

Of these, the most obvious is inside the container itself, among the cargo, but this is difficult. The back doors are usually locked and breaking in is noisy. In Calais, some criminal gangs have keys that will open these doors, but they charge between €500 and €7,000 a time and often steal the migrants’ money. Some people try to run after the lorries and open the doors when the vehicle is in motion but this, too, is hard. Instead, many others try to hide on the underside of the lorries, crawling below the back section and manoeuvring their bodies on top of the rear wheel axle. There is just enough space to hide here, lying above the axles and balancing with your hands and feet on top of the wheel arches on either side of the vehicle. (The young man who hid under the Coles family’s motorhome probably used a similar method.) It is not easy to hold on, particularly when the vehicle is moving, and those who fall off risk being crushed to death under the wheels.

Six other Eritrean men were with Samuel that night, which meant they could push one another forward, along the narrow gap that separates the rear axle from the underside of the container above, until they reached the middle of the vehicle. Most lorries of this type have an extra storage space there, in between the two sets of wheels – a metal frame that holds a box or a spare tyre – and it was on top of one of these boxes that the six men squeezed together. “You couldn’t move your arms,” Samuel recalled, “and there wasn’t much air to breathe.”

The men hid at midnight and the lorry did not move until 5am, and in all that time they dared not move or make a sound, for fear of being discovered. Once on the motorway, the breeze allowed Samuel and his companions some fresh air, but they still had to remain concealed for another four hours as the lorry was transported by train through the tunnel and towards its destination in England. When they reached Kent, the men started banging on the container to alert the driver, but it was only when the lorry reached its depot several hours later that a staff member heard them, helped them climb out, and called the police. Samuel told officers that he was a refugee and wanted to claim asylum; they kept him in cells overnight before handing him over to immigration enforcement staff, who took him to London.

When I arrived at the hotel in the Crystal Palace area to meet Samuel, I was surprised to find an ornate white Victorian building near a park, with a blue plaque on the front wall noting that the French novelist Émile Zola had once lived there. A friend who resides nearby told me later that the hotel usually hosted coachloads of German schoolchildren. But recently it had been rented by the Home Office, an early sign of a crisis, news of which reached the media a few weeks subsequently. Companies contracted to provide housing for asylum-seekers (the system was privatised in 2012) had been failing to do so, forcing the Home Office to step in and find accommodation at short notice for hundreds of people. This led to a flurry of headlines about asylum-seekers being housed in “luxury” hotels. In reality, their living conditions were crowded and dirty. Some 600 people had been placed in Crystal Palace, even though the hotel had only 98 bedrooms.

Samuel and I walked along the high street to find a café where he could sit and tell me about his journey. The night underneath the lorry was only the last stage of a 9,000-kilometre odyssey, during which he witnessed a friend die of thirst in the Sahara Desert, squeezed into a leaking smuggler boat to cross the Mediterranean from Libya, and was so badly beaten by French police that he needed hospital treatment.

Tens of thousands of Eritreans, men and women, make similar journeys to Europe every year to escape from compulsory military service, which can last for up to 25 years in their country. This year so far, 37,000 Eritreans have come to Europe to seek asylum, according to the United Nations High Commissioner for Refugees, making them the second-largest refugee group after Syrians. Most of the Eritreans go to Sweden, Germany and Switzerland, not Britain.

While still in France, Samuel told me why he’d wanted to reach the UK: he spoke English and he had heard there were jobs here – he was willing to do anything to earn a living. France was less attractive; he had friends who had been left living on the street because of a housing shortage in the asylum system. But Samuel had no idea how Britain’s asylum process worked, and now seemed bemused to have ended up where he was.

The biggest shock of all was discovering that most of the others in the hotel had made much simpler journeys. If you have the money to apply for a visa, or to buy false documents, you can travel to the UK through a legal route and then claim asylum on arrival. Airports are the single biggest route into Europe for irregular migrants, according to the EU border agency Frontex.

“Our journey is very long,” Samuel told me, referring to those who traverse the Sahara. “We cross many countries, sacrifice our life. But many people in the hotel arrived on flights. When they hear about us, they are surprised – they say our life is already passed.”

The next day I caught the P&O ferry from Dover to Calais, at the start of a weekend of protests there. Until May, the first thing you would have seen on leaving the French port on foot towards the town centre was a makeshift tent camp, home to several hundred migrants. Others lived elsewhere in the town, in squatted buildings and self-built camps. Most had come from countries where conflicts or internal repression were rife, such as Afghanistan, Iraq, Syria, Eritrea and Sudan. As the volume of migrants living rough in Calais grew steadily leading up to the summer, the police demolished the tent village and several other camps, sometimes using tear gas to clear them. Riot police had been sent to patrol Calais, and the migrants complained of rough treatment.

On the Friday afternoon, around 150 migrants from Sudan and Eritrea marched through the terraced streets of working-class Calais chanting, “We want human rights!” under the impassive, occasionally hostile gaze of the town’s people. Every now and then, the protesters would switch to a chant of “UK! UK! UK!”. Two days later, on the Sunday, the anti-migrant group Sauvons Calais (“let’s save Calais”) held a rally outside the town hall, with the support of activists from several extreme-right political parties who had been bussed in. As their leaders addressed the crowd, calling for fire hoses to cleanse the town and blaming the traitors and “collaborators” in government who had allegedly opened the door to migrants, a group of masked anti-fascists tried to attack the gathering, but was stopped by police.

Calais has long been a stopping point for undocumented migrants hoping to reach the UK. In 2002, after a flurry of negative press coverage, the British government pressured France into closing a Red Cross camp at Sangatte, just outside the town, because it was deemed to be attracting migrants. Since then, the local policy has been one of deterrence, by making conditions as harsh as possible for the unwanted visitors. But as migrant numbers in Calais have recently swelled – from a few hundred last winter to the present high of well over 2,000 – the sight of destitute refugees trying increasingly desperate methods to reach the UK has drawn unwelcome attention. Fights have broken out between migrants of different nationalities as they compete for access to the lorry parks. To circumvent the smuggler gangs, groups of migrants have tried running into the ferry port en masse, hoping that a few of them will be able to hide before the police catch them.

On the Saturday between the two protests, I visited one of the largest migrant squats, a former scrap metal yard nicknamed Fort Galoo, after the name of the company that was once based there. It had been reclaimed by members of the pan-European No Borders Network, who work to disrupt what they see as unacceptable state controls on migrants. Fort Galoo was surrounded by high walls, with a small office building in one corner. On its ground floor was a generator surrounded by a spaghetti junction of extension cables. At sunset the power would be turned on for a few hours and a scrum would develop as the migrants crowded round to charge their phones. About 100 people, mainly East Africans, lived upstairs or in tents in the courtyard. There was a fire hose, still connected to the mains, for washing, and a few toilets donated by the charity Médecins du Monde. Two ageing portable buildings had been made into women-only living quarters. Female migrants are in the minority in Calais but face extra hardships: they run the risk of sexual harassment or assault and because they tend to avoid the more physically demanding methods of hiding, such as hanging beneath vehicles, they are open to exploitation by people smugglers.

Looking around the yard, I noticed a group of men and women sitting on plastic chairs in a semicircle. They were being lectured by a man who was writing out French phrases on a whiteboard. He wore a shabby corduroy jacket and spoke to his audience in Arabic-accented English, ostentatiously pronouncing phrases such as “education is the progressive discovery of our own ignorance”. Mekki was originally from Sudan and now resident in Calais, and he came to the squat most days to give the residents language lessons to help them negotiate life in France and Britain. He did this for free: in Calais, there is a whole community of volunteers, from the No Borders radicals to individual well-wishers, who help feed, clothe and advise the migrants.

During a break in the lesson I chatted with some of Mekki’s students. They asked me to conceal their identities. The first was a middle-aged woman from an East African country, who wore a matching blue-patterned dress and headscarf and had been carefully writing down phrases in an exercise book. She told me she had been a scientist studying how to increase grain output in her famine-prone home region. But a government crackdown on her ethnic group had disrupted her work. So one day she left home, travelled overland to Egypt and took a boat across the Mediterranean. She had two teenage sons, and the first they knew of her plan was when she phoned them a fortnight after she left and said, “I’m in Calais.” Why not stay in France? I asked. She looked at me a little sternly. “I’m 40 years old,” she said. “Language is the main problem. I speak English, not French. I can’t start ‘A, B, C’ again if I want to do a PhD.”

By now, Mekki was ready to begin teaching again. He asked me to come to the front and explain the meaning of some English proverbs he had written on the board. I read them out and the students repeated them softly in unison: “A rolling stone gathers no moss.” “Before you judge a man, walk a mile in his shoes.” As they did so, I recognised some of the people who had been chanting angrily at the migrants’ demonstration a day earlier. The last proverb was one I had not heard before: “A bush grows best where its roots are.” I could not resist asking: this one was wrong, wasn’t it? Surely people can feel at home wherever they settle. A dozen people looked up at me and shook their heads.

***

Say “refugee”, and usually it evokes a sympathetic image: a terrified family on the run from a war zone, in urgent need of protection. Say “economic migrant”, how­ever, and the picture gets murkier. If they are fleeing poverty and not war, so what? Do we owe them a living? Are they even here to work, or just to scrounge off our welfare systems?

But it is possible to be one and the same thing. Several hundred thousand people apply for asylum in Europe each year, but once there, refugees need the same things as the rest of us: not just shelter, but a chance to build a life. Many try to do what millions of EU citizens do every year and travel to the parts of Europe where they think they have the best chance of achieving that.

Standing in their way is a treaty known as the Dublin Regulation, which stipulates that refugees must claim asylum in the first EU country they enter. When they first claim asylum, their fingerprints are taken and placed in a Europe-wide database: if a refugee is stopped in, say, Sweden, but the database shows that he first arrived in Italy, he can be sent back there. The Home Office told me that over 12,000 asylum-seekers have been removed from Britain under the Dublin Regulation since it came into force in 2003.

The system does not always work. In late September, a young Sudanese man con­tacted me on Skype. “Hassan” and I had first met in February, when he was living under a bridge by the canal that rings the centre of Calais. He spoke good English, and loved American R’n’B. “I don’t like hip-hop, I can’t understand the words,” he’d said. “Except Eminem. ‘Lose Yourself’, from 8 Mile? Beautiful. I go to the internet and read his lyrics and sometimes I think they’re to do with me.”

Hassan had a Twitter account, so we swapped details. But the account remained silent for months, and I had begun to wonder where he was. Had he become a casualty on the motorway outside Calais? Then one day in August, I saw a tweet: “Fuck the police! They ain’t shit but a legal gang.”

Hassan, now 23, had spent almost his whole adult life in Europe. When he was 18 and still living near Khartoum, Sudan’s capital, he was briefly arrested on suspicion of being a member of a rebel militia. It was a case of mistaken identity, he said, but the police put him under surveillance. He fled to Turkey on a false passport and then to Patras in Greece, where he claimed asylum. That was in 2009, the year after the global financial crash, an event that exposed profound inequalities between EU member states and sent hundreds of thousands of Greek citizens abroad in search of work. Hassan needed to work for a living, too, but he faced a double bind. First, the growth of racism in Greece had made daily life intolerable for him and other black immigrants, as they faced frequent harassment from the police and supporters of the neo-Nazi Golden Dawn movement. Second, Greece’s dysfunctional asylum system left refugees for years at a time with “temporary” iden­tification documents that gave them no right to travel.

In early 2014, Hassan decided he needed to get to Britain. He had cousins in Cardiff and he wanted to study to become a film director. At Patras, a port city that faces western Europe, he sneaked on to a ferry bound for Italy and hid beneath a lorry. To know which Italian port you’ll arrive at from Patras, you have to count the hours the journey takes: 24 hours and you are in Ancona; if it is 35 hours – as it was for Hassan – you have reached Venice. During the entire voyage he had to stay out of sight, scooping water from the floor when he got thirsty.

It was night when Hassan arrived at the port of Venice, which is some distance from the city itself. On the road in, police asked to see his documents. All Hassan had was his “pink paper”, the temporary document issued to refugees in Greece. The police could have arrested him but they chose not to: a 2011 ruling by the European Court of Human Rights that Greece detains refugees in inhumane conditions has led to most EU states suspending Dublin returns there. National courts also sometimes consider other economically struggling countries on the edges of the EU – Bulgaria, sometimes even Italy – unsuitable for returns. The deep inequalities within Europe have thrown the Dublin system into crisis.

After walking for several hours, Hassan reached the outskirts of Venice – an industrial sprawl built inland from the historic city – where he came across a Bangladeshi man. Hassan asked him for directions to the nearest mosque. He was tired, hungry and cold and had only €2 in his pocket. At the mosque he told the imam his story. Wait here, the imam said; after people have come to pray we will have a collection for you so you can buy a train ticket to Milan.

Italy’s second-largest city, Milan has become a hub for migrants who want to make clandestine journeys to northern Europe. It is a ten-hour drive to Berlin from there, or just eight to Paris. Syrian refugees here often try to reach Sweden or Germany, where they have a good chance of being granted asylum. Others with less certain claims might head for London, where they have heard there is work available on the black market. Milan is a multicultural city and a newly arrived migrant can find people from similar backgrounds who are willing to help. Europe’s police forces are aware of these underground networks: on 13 October, 25 EU states launched a two-week operation to round up, detain and deport “irregular” migrants and to gather intelligence on their methods of travel.

When Hassan reached Milan, he met an Eritrean man outside the train station who took him to a part of the city where other Sudanese people lived. He stayed there for five days until a relative was able to wire him money, then he caught a train to Ventimiglia, the last stop on the coastal line that leads into France. There has not been much of a border there since the Schengen Agreement, but in 2011 the French government temporarily blocked trains coming from Italy because of the number of undocumented migrants on them. When Hassan crossed, the border was open: he caught a train from Ventimiglia to Nice, and then Paris. After three days sleeping on top of the air vents outside a Métro station, he boarded another train, to Calais.

When we talked over Skype in late September, I asked Hassan what had happened during the months when we had lost contact. “I began getting tired of trying and failing to get into the UK,” he told me. Every time he hid under a lorry, it turned out to be going to the Netherlands. “The more you fail, the more upsetting it is to have to walk back to Calais in the morning.”

He was on the verge of giving up when a friend told him that refugees in Scandinavia were treated better than in Britain, and suggested he go there. He went back to Paris and paid a Sudanese contact €500 to drive him north. He was living in a refugee reception centre when we spoke, and was happy about where he had ended up. “They know we have come from struggles,” Hassan said, “and they don’t want us to be in our rooms all day on the internet. They teach us; they really want us to learn the language.”

In early October I visited Augusta, a port on the east coast of Sicily. On the quayside, a yellow powder that stained the tarmac was swept upwards by the breeze, stinging my eyes. It was sulphur, a by-product of the oil refineries a few miles south from where I stood, watching people disembark from an Italian navy patrol boat and taking their first steps on European soil.

There were more than 100 of them: families with young children from Syria and Gaza; teenage boys and young men from Sudan; young women from Somalia. Some had only the clothes they were wearing, while others carried small bags of possessions. A few were so weak that they had to be carried off the boat. One Arab man strode down the metal walkway with a laptop briefcase as if he was on his way to the office.

Augusta is one of Italy’s major commercial ports. Its fate has long been linked with events in North Africa. In the past decade many European powers, including Britain, sought to strike deals with the oil-rich regime of Muammar al-Gaddafi, but Italy was the single biggest beneficiary. At one point a third of the country’s energy requirements were met by Libyan oil, much of which passed through ports such as Augusta. Other deals were struck, too: in 2008, under an agreement between Gaddafi and Italy’s then prime minister, Silvio Berlus­coni, Libya committed to halting the flow of migrants setting sail for Europe from its Mediterranean coast.

Since the fall of Gaddafi in 2011, that deal has unravelled. Libya’s coast is now a major launching point for smuggler boats carrying migrants across the Mediterranean. The frequency of such crossings has increased as the world experiences its worst refugee crisis since the Second World War. It is no longer possible to claim asylum at the overseas embassies of most European states, and the EU has been investing heavily in fences and surveillance at its land borders, which pushes more people to attempt journeys by sea.

Europe takes only a small proportion of the world’s refugees – some 86 per cent are hosted by developing countries, according to UNHCR – but the Mediterranean is the world’s most deadly route for migrants. More than 3,000 people drowned there last year. In October 2013, after one particularly deadly sinking off the coast of the island of Lampedusa, the Italian navy launched Mare Nostrum, a search-and-rescue operation to find migrants at sea and bring them to land at ports such as Augusta.

At the quayside, police officers wearing medical face masks and stab vests gave the signal to move. Nobody said much as we walked away from the water’s edge towards a white tent that offered shelter from the midday sun. The migrants, I later discovered, had been lost at sea for a week. Now, all you could hear was the slow tramp of feet over tarmac.

A man turned round to me and asked if I had any cigarettes. His name was El Haji, he said, from Darfur. “You’re from London? See you there,” he joked.

Already these people were being monitored and tracked by EU officials. Their final destinations would be determined by their wealth and their ability to negotiate Europe’s asylum system. Those with the money would pay €800 for a taxi ride from Sicily to Milan. Others would try to make their way up the Italian mainland in stages. Many would stay in Italy and chance their luck in a country with a weak economy, already struggling to accommodate the 150,000 or more refugees who had arrived on its shores this year.

First, though, they needed to be documented. Outside the white tent the refugees were told to sit on the floor, in the sun, as they waited to be registered and fingerprinted. Even in October, temperatures in Sicily can reach 30°. A Syrian man who had a baby boy strapped to his chest in a sling asked for some sunscreen but was told to wait. The heat got too much for him and he started walking unsteadily towards a medical tent run by Médecins sans Frontières. His wife walked with him, taking hold of their son. When the man was a few metres away from the tent, he took back his boy and held him, somewhat defiantly, for the last few paces. As he reached the doctors, they took his son and pointed towards a camp bed. He collapsed on to it.

The next day, I visited the old town in Augusta, at the end of a peninsula on the other side of the bay from the port. On a dusty road buckled by an earthquake that shook the town over a decade ago, I found an old school building that had been hurriedly pressed back into service to house children rescued from the sea without their parents. Under Italian law, adult refugees and their families can be put up at reception centres around the country, but unaccompanied minors must be looked after by the local council in the town where they arrive. About 4,000 of these minors, mainly boys, had passed through Augusta since the start of Mare Nostrum; nearly 3,000 were being looked after; the rest were unaccounted for.

There were several dozen teenage boys living at the school when I visited. Most came from West Africa; there were smaller groups from Egypt and Bangladesh. They slept on camp beds, ten to a room, and the building was left unsupervised in the evenings and at weekends. They got three meals a day, but no money, and spent much of their time wandering around the town, begging outside supermarket doorways. The people of Augusta were generous, if disturbed by the humanitarian crisis unfolding on their doorstep.

The boys pooled their money to buy cheap smartphones, and in the evenings, some of them would sit in a row on tiny primary-school chairs outside the school gates, trying to catch a wifi signal from the pizza shop opposite. They chatted on Facebook with friends and family back in their home countries, and posted photos of themselves pretending to buy expensive clothes and electronic goods in the shops on Augusta’s main street.

One of the boys, Ibrahim, was 17 and from Guinea, a poor country with rich natural resources including bauxite ore, the raw material for aluminium, without which modern travel – in trains, aeroplanes, lorries, boats and camper vans – would not be possible. First Ibrahim had gone to Senegal to study, but his parents couldn’t afford to keep paying for his education. Then he had tried to become a tailor and went to Mauritania to look for work. When that did not work out he went home again, and decided to set out for Libya. He’d never intended to come to Europe, but the chaos in Libya, where the assault and murder of black Africans has become commonplace, was such that he decided to flee. I asked Ibrahim whether he’d like to go back to Guinea. “Life there is not very stable, you know,” he said.

In October, Italy announced the end of Mare Nostrum. The intention was always that it would run for a year as an emergency programme, a stopgap until a rescue operation supported by all members of the EU could launch. But it is unclear whether the replacement operation will focus on saving lives, or on keeping boats out of European waters. The British government’s position is that the rescues should stop, because they only encourage more migrants to attempt the crossing. All of the people I interviewed for this story made their first journey to Europe in a smuggler boat across the Mediterranean. Our government believes that, had any of them drowned, it would have been a useful deterrent to others.

Daniel Trilling is the editor of New Humanist magazine