I was halfway through Caroline Moorehead's Human Cargo when the Tory leader, Michael Howard, placed his advertisement in the Sunday Telegraph calling for a cap on immigration into Britain. Opportunistic politicians who exploit the public's fears about asylum-seekers are among the minor villains of Human Cargo. Indifferent and cynical as such figures are, they occupy Moorehead only in so far as they offer evidence of how little understanding and sympathy is extended to refugees. Since the mid-1990s, the total number of displaced people worldwide has fallen from 19 million to 12 million, yet during the same period, Moorehead argues, global attitudes have hardened. Refugees have become a despised underclass, vilified by politicians and the media, and defended only weakly by an ineffective aid system.
"Displacement is like death," writes an unnamed Palestinian poet quoted by Moorehead. "One thinks it happens only to other people." Human Cargo is filled with the stunned accounts of ordinary folk - parents, children, husbands and wives - who have found themselves swept away on the currents of civil war, natural catastrophe and ethnic dispute. Moorehead goes in search of their stories, travelling to tented refugee camps in Guinea, Palestinian settlements in Lebanon, communities of Liberian boat people in Sicily and the detention centres of Australia's "Pacific Solution". Allowing the refugees to speak for themselves, she recounts their experiences in sparse, unflinching prose.
Through her, we meet the likes of Abdula, who saw rebel soldiers in Liberia burn his father over an open fire before hacking him into little pieces; Mohamed, who watched as his godmother's head was kicked about like a football; and Abu, the boy soldier forced to slit open a pregnant woman's stomach. Such stories are horrifying. Others that Moorehead recounts verge on the surreal - for instance, that of the community of Sudanese asylum-seekers who, fleeing war on the equator, have been permanently resettled in the Arctic Circle, in the perpetual winter darkness and -35 Celsius temperatures of Finland.
From Australia's offshore detention centres to Britain's xenophobic press, Moorehead also documents how refugees and asylum-seekers are received in the west. In a chapter devoted to the evolution of Australia's draconian immigration system, she describes the political crisis that was triggered in 2001 by the arrival in Australian waters of a 20-metre fishing boat carrying 438 Afghans. The government's response was to devise the Pacific Solution, involving offloading the passengers and all future asylum- seekers in places such as the islands of Papua New Guinea. Here they languished in brutal detention centres, without access to lawyers and beyond the reach of Australia's courts. The numbers of asylum-seekers to Australia fell dram- atically, but there was a high moral and financial cost. Interviewing some of the children detained for many months, Moorehead encountered numerous incidents of mental illness and self-harm. One boy, deciding he wanted to die, was found digging his own grave. Another, asked why he had burned his hand with a lighted cigarette, replied: "Because I can't feel anything."
Yet this is not simply a book about victims. In Tijuana, Mexico, Moorehead watches would-be migrants return again and again to try to scale the fence separating them from the United States of America, and notes that not all those seeking asylum are fleeing persecution. Migration, she argues, is the unfinished business of globalisation. In a world in which trade and communications are becoming increasingly fluid, the final, enduring frontiers are the physical ones - the fences, guard posts and customs points - that separate rich nations from poor. There is, she acknowledges, "no magic panacea" to resolve the well-rehearsed argument between liberals who argue that denying immigration is a violation of basic human rights and conservatives who fret about the collapse of society under the weight of foreign numbers. Even the economic arguments advanced in favour of immigration do not necessarily stand up.
Between 1999 and 2000, asylum-seekers, refugees and other migrants made a net contribution to Britain of roughly £2.5bn. Yet there will always be those who are too damaged, too frail or too inflexible to find work in a new country. As a con-sequence, open asylum policies cannot simply be justified on the grounds of monetary gain or even international responsibility. It's about morality, writes Moorehead: "In an age of globalisation, it is simply not possible to ignore the world's dispossessed. How a state deals with its refugees should be a measure of its social and political health."
For all her indignation, Moorehead betrays little explicit anger. Instead, she allows the refugees to relate their own experiences and reveal the nightmares they have been through. This strategy has its drawbacks. It is easy, confronted with one harrowing story after another, to find yourself reeling in shock. To her credit, however, Moorehead manages to write poetically about even the grimmest of lives. She describes exile as "a form of mourning" punctuated by traumatic memories of torture, flight and the death of loved ones, which "flare up, like sudden fires, into despair". And in the most moving section of the book, she strays from straight reportage in an effort to understand the psychological state of refugees.
It is here that we meet Lamine, who was jailed and tortured in Algeria for six years from the age of 18, was stabbed by Algerian government agents after escaping to Spain, and who finally resettled in a cheap hotel in King's Cross, London, suffering from depression, psychosis and flashbacks of humiliation and torture. It is often only after refugees reach a country of safety that the pain of their past catches up with them. Moorehead offers the suicide of Primo Levi as an example of the unbearable weight of memory, which can haunt victims of persecution even decades after their original suffering.
This, she argues, is the common experience of exiles, half of whom suffer from post-traumatic stress disorder and up to 90 per cent of whom show signs of depression. When treated by doctors or therapists, most "reported a feeling of profound worthlessness. Some spoke of suicide . . . They spoke of 'frozen memories', obsessive and intrusive thoughts that came back, unchanged, again and again." There is, Moorehead notes drily, "something singularly traumatic about the combination of forced exile and extreme violence". To which you could add the disorientation of arriving in a safe country only to find that your story is dismissed as exaggeration or an outright lie.
The truth of exile, writes Moorehead, is that no one wants to be a refugee. Almost every asylum-seeker would prefer to return home if it was safe to do so. Failing that, what they hope for, at the very least, is to be treated as an individual rather than another piece of human cargo.
Ekow Eshun's Black Gold of the Sun: searching for a home in England and Africa will be published by Hamish Hamilton in June