Katja is running around a meadow on Blackdown Hill on the border of Surrey and Sussex. She grins, her yellow dress a blur amid the overgrown grass, but as she passes an apple tree, she stops beside her friend Nastya. The eight-year-old takes her friend's hand and they walk along clutching each other, heads down, not saying much.
Like the other Belarussian children around them, they look young for their age - small, slim and fragile. Katja doesn't speak much, even in her native Russian, and her eyes are filled with a distant blankness.
The effects of that explosion are now evident across Katja's homeland. Cases of children's cancer have jumped 60-fold since Chernobyl's nuclear reactor blew up in April 1986; the number of children in the area with thyroid cancer has increased by a factor of 50. Belarus has the world's highest rate of children's leukaemia, brain tumours and kidney cancer.
Katja was born half a decade after the meltdown in neighbouring Ukraine, but caesium radiation still blights the region's produce and water, and affects every mother and child.
In a week's time Katja will go home, along with Nastya and more than a thousand other young Belarussians who have spent the summer in private homes across Britain. They have had a dream summer holiday, courtesy of a charity and hundreds of British people, many of whom paid for their air fares and their entire stay.
Some people from their country are staying longer. Last week Vasya Kurbako - a 16-year-old orphan whose jaw has been severely disfigured by the radiation he ingested when he was four years old - came to the nation's attention when it emerged that the Home Office was threatening to send him home, away from his adoptive Scottish parents, because his immigration papers were out of order. His foster-mother in Dumfries, Chrissie McCaffery, said she would prefer to go to jail for defying the Government than send Vasya - who has been here for five years - back home.
But the deportation order has now been suspended pending a review and Home Office sources told The Independent that Vasya was likely to be allowed to remain here as long as his adoption papers can be completed - something the McCafferys' solicitor, Anne Guthrie, says she is confident will happen.
Vasya, who has no family at home and needs a major operation on his cleft palate - may be one of the luckier ones. There are now about 2,000 Belarussian children in Britain. Many of them, like Katja and Nastya, have loving parents at home, but each day in their homeland they eat the products of the irradiated soil of one of Europe's most impoverished countries.
The children are here courtesy of Chernobyl Children Lifeline, a Surrey- based charity that organises visits by more than 3,000 eight-to-16-year- olds every year for two or three months. Victor Mizzi, the charity's director, started it seven years ago after visiting Minsk, the Belarus capital. "Practically every child in Belarus is affected by Chernobyl radiation, and it will continue for generation after generation," he says. In his Tudor cottage on the Surrey-Sussex border, the retired businessman has an album of photographs he took on a visit to the city's children's hospital. Kids pose un-self-consciously with deformities that make the eyes water: a small boy with tumours growing out of every part of his body; a girl with hands instead of feet.
The Belarussian children sitting quietly in his back garden, guarded by their English "parents", look quite normal at first. They are beautiful kids, fine-featured, with high cheekbones, clear complexions and lovely blue or green eyes. Ksenya and Sveta are 16 and 17, and, after nine visits between them, including a stint for each in a Kent boarding school, they speak near-perfect estuary English. What does Sveta think of England now? "It's awright," she intones approvingly. How long was Ksenya at boarding school [paid for by her English "parents"]? "Six maanfs." Did she like it? "Yeah." There is obviously a lot more in these girls' minds, but they are shy. Were they looking forward to going back? There was a hesitation: yes, they were looking forward to seeing their families and friends, but they were not looking forward to going back. Details were unforthcoming. They sounded like normal enough teenage girls until the photographer asked them to stroll around for some pictures, and then something dawned: they looked 13 or 14 years old, not the late teens they really are.
More poignant was Katja, who is eight years old but looks five or six. Instinctive and sharp, but monosyllabic, she answers questions rapidly. Did she like Britain? "Da." What was her favourite thing here? "The pub." Was she looking forward to going home? There was a minuscule pause. "Da." Her sharp blue eyes clouded over.
Kostya is 14, smart and virtually fluent in English. He had had, he told me matter-of-factly, an operation to remove a tumour on his lungs when he was eight and one to remove a brain tumour when he was 10. He is now fully recovered. Kostya is good-looking and engaging: when he accompanied Victor Mizzi on a trip to Canada last month, all the girls in the class he visited fell in love with him. He wants to be a fighter pilot. Was he looking forward to going home? "Not really," he says. There is much more to the trips than pampering and the tourist trail. Some children receive treatment for their radiation sickness - leukaemia, thyroid cancer, brain tumours and physical defects are more than 200 times more common in children from Minsk than in children from Macclesfield, and many other suffer "minor" effects such as jaw and gum problems. Having lived most of their lives on irradiated food, much of it low in nutrients, their immune systems are dangerously vulnerable.
"A couple of months over here eating a proper diet of uncontaminated food will have enormous positive effects on their health," says Paul Campbell, a consultant orthopaedic surgeon in Chester who last year operated, free of charge, on a visiting Belarussian child disfigured at birth by radiation.
One of the children's consultants in Belarus was quoted last year as saying that "two months in Britain is worth two years at home", in terms of the children's physical development.
Mr Mizzi tours Belarus three times a year looking for parents who want to send their children abroad: many, he says "are queuing up" to get their children on a visit, having seen the effects on those who have returned. Demand is so great that British host parents who want to receive a visit from the same child often have to pay for it themselves; those who have not come before are first in the queue.
"You can see the change after a few weeks," enthuses Doreen Antill, who hosts Ksenya, Sveta and Ludmilla. "They look healthier, their skin glows, and they're smiling and more confident." After lunch, the children leave with their hosts, a vaguely incongruous group, but a happy one nonetheless. This time next week the youngsters will be back in a place where caesium 137 runs through the veins of everyone they know.Reuse content