WHEN Svetlana Alexievich met Mikhail Gorbachev for the first time several years ago, he told her: “For such a small woman you write big books.” To which the mighty Belarussian writer responded: “You are not so big yourself, yet you could destroy an empire.”

The last leader of the Soviet Union was amused, recalls Alexievich, who is sturdily built and just over five feet tall. She will be 68 years old on May 31 and has won numerous international awards, including the 2015 Nobel Prize in Literature for “her polyphonic writings, a monument to suffering and courage in our time”. She is the first person to receive the prize for books about living people.

Indeed, Gorbachev, whom she likes, was one of the first to congratulate her. He was only one of many international politicians, including the French and German presidents, to recognise the honour, while thousands of well-wishers wrote to her.

She is, however, still waiting for Vladimir Putin’s felicitations. It will be a long wait, she acknowledges, speaking through an interpreter when we meet at Pushkin House, the Russian cultural centre in London. But then, she adds drily, nor has she heard from the president of her homeland, Alexander Lukashenko, the former Soviet army officer who has run Belarus since 1994, and who has the dubious distinction of being Europe’s last dictator.

On the announcement of the prize, he was forced to congratulate her on TV, although her books are all but banned in Belarus, where she still lives in Minsk after a dozen years travelling. Two days later he declared that she decries the peoples of Russia and Belarus in her work. In Russia, there was nothing but vitriol; she was branded “a traitor”. “It’s the new patriotism in Russia, which is again living this philosophy that we are a besieged fortress.” She is, however, in good company. Nobel laureates Bunin, Brodsky and Pasternak were also rejected and rubbished by the Soviet leadership.

The first author of non-fiction to win literature’s top award for more than half a century – the last was Winston Churchill, who famously remarked that “Russia is a riddle wrapped in a mystery inside an enigma” – Alexievich tells me that it is in order to make sense of that very puzzle for herself that she has written five books.

Her first, War’s Unwomanly Face, is made up of interviews with hundreds of women who fought with the Red Army between 1941-1945. For The Last Witnesses, she spoke to people who had experienced the Second World War as children; then she wrote Boys Of Zinc, featuring the voices of Soviet soldiers, who fought in the doomed war in Afghanistan, their mothers and widows (the title refers to the sealed zinc caskets in which their bodies were sent home). For Chernobyl Prayer, she crafted a vivid collection of monologues from survivors of the nuclear disaster that are almost unbearable to read.

Each of these shocking books, lyrically written in Russian, is an acknowledged masterpiece, based on hundreds of documentary interviews she has conducted with thousands of people – she often returns more than 20 times to one interlocutor alone – who have lived through the horrors of war, the Chernobyl disaster, the downfall of an empire. She devotes years to writing each book.

Tapping the cover of Second-hand Time, the final book of the five, about life during and after the collapse of the Soviet Union and which has just been published in an English translation, she explains that they are collectively and ironically entitled Voices From Utopia, “an encyclopedia of the Red Empire”. These oral histories read like magnificent, 19th-century Russian novels since they are Tolstoyan in their range and depth, while Dostoevsky is also an influence.

They are, she says, “novels with voices, histories of the soul and a history of feelings”. They are not journalism. “Journalists do not write about human feelings.” She is a writer not a reporter, hymning the extraordinary wisdom and courage of ordinary people who have suffered unspeakable pain and misery, although there are jokes, too, in the telling.

A born listener, she describes earwigging on trains, in kitchens, cafes, market places and at street corners. Mostly she is invisible, never inserting herself into the narratives, which often come with titles as if from Russian folk tales, such as On The Beauty Of Dictatorship and the Mystery Of Butterflies Crushed Against The Pavement in Second-hand Times, or Monologue On How Some Completely Unknown Thing Can Worm Its Way Into You, from Chernobyl Prayer. She will often include only the name, profession and age of a subject, while some remain anonymous like a Greek chorus. Then we hear the individual voices, bearing witness.

“I let people speak for themselves; I do not ask questions,” she says of her interviews. “I have conversations with people, which I tape on a dictaphone like yours,” she says. She has them transcribed. “If I did it myself it would take 50 years to write one book!” she exclaims. The writing takes a long time, anywhere between three and 10 years. Often, she will edit 300 pages of transcript down to one or two paragraphs.

Alexievich was just five years old when she knew she wanted to be a writer – “not a journalist” – although she did work at a newspaper after studying at Belarus State University. The daughter of two village schoolteachers, she was the eldest of three, growing up in rural happiness in southern Belarus.

Her parents are dead – her wonderful father remained a devout communist to his dying day – as is her sister, a doctor. “Already diagnosed with cancer, were it not for Chernobyl she would have lived longer,” says Alexievich when we talk at length about the terrible consequences of the greatest technological catastrophe of the 20th century. “Death was everywhere, although strangely Chernobyl Prayer is about the beauty of life.”

Unmarried, Alexievich adopted her late sister’s then four-year-old daughter, who is now a teacher in Minsk. She has a 10-year-old daughter and Alexievich’s sweet-featured face lights up when she speaks of her granddaughter, who is sitting school exams as we speak. “We are good friends.”

All of her own childhood was spent listening avidly to women in the village, particularly her grandmother, talking about the past. “I always remembered those women’s voices so when I first started writing oral history I looked for women who had stories similar to those I first heard. Women tell things in more interesting ways. They live with more feeling. They observe themselves and their lives. Men are more impressed with action, the sequence of events.

“When I was a child, women spoke to me of how all they had was their memories, how their husbands went to war and never came back, so many tragedies. That chorus of voices filled my consciousness. It was part of life itself. I went back to interview many when they were very old for War’s Unwomanly Face.”

She rarely loses a night’s sleep over the tragedies that have filled her working days. “I don’t have nightmares – these things did not happen to me. But you ask what I shall do next. I am writing two non-fiction books, one about love, another about old age and dying. I have already done many interviews for both. I will never write fiction. I am tiring of it.”

Having supped her fill of horrors, what gives her solace? “Nature,” she replies. “I have a house beside a forest and I walk there for hours – and my granddaughter, of course, who calls me Sveta.”

Before we part, I ask Alexievich to sign my copy of Second-hand Time. She writes a dedication to me in Russian which reads: “Let us have faith in the word, that it is not powerless, and serve it.”

Second-hand Time: The Last Of The Soviets, by Svetlana Alexievich, translated from the Russian by Bela Shayevich (Fitzcarraldo Editions, £14.99). Chernobyl Prayer: A Chronicle Of The Future, by Svetlana Alexievich, translated by Anna Gunin and Arch Tait (Penguin, £9.99).

Boys In Zinc will be published in October; War’s Unwomanly Face and Last Witness will follow in September, 2017.