The critics of Vladimir Putin - Russia's Prime Minister, and former KGB agent - have a strange habit of being found shot or stabbed or poisoned. This week, I met a man who is half-expecting an assassin's bullet - here, in London. He is not alone. Ahmed Zayakev - a big, broad man with a grey beard and grief-soaked eyes - says: "I remember holding a press conference near here with my dear friends Alexander Litvinenko and Anna Politkovskaya. Now they are murdered, and I am the only one left. But I have no right to sit in a hole and shake. I have to speak."
Zakayev is a Chechen, and his people have been pounded by Putin and his predecessors for too long. The people of his small mountainous province in the Northern Caucusus - rich in natural resources - are one of the most abused populations on earth. In the 1940s, Joseph Stalin deported every single one of them to Siberia and elsewhere. A third died on the way there; a third died on the way back. "My grandmother never recovered from this," Zakayev says. When the Soviet Empire finally fell in 1991, the people of Chechnya tried to carve out some autonomy from their vast neighbour - and they were pummeled into submission by aerial bombardments and ground invasions that killed hundreds of thousands of people. "There were corpses everywhere. I see them [in my mind] all the time," Zakayev adds.
The current killing-spree of Russian dissidents is, in part, an attempt to silence criticisms of these crimes. Anna Politkovskaya was a journalist - one of the greatest of our time - who traveled to Chechnya to expose the mass torture and slaughter by Russian troops there. She believed that Chechnya was a test-bed for tyranny that was spreading back across Russia itself, leading to "the re-establishment of the Soviet Union." As if to prove her point, first she was poisoned. She survived. Then she was shot dead in the lift-shaft of her apartment block. Last week, the trial for her killing ended in Moscow. The case conspicuously avoided asking who ordered her killing, or why. It focused on "the middlemen" - the alleged driver and look-out for the assassin. They were acquitted. Nobody will be punished now.
Alexander Litvinenko was a Russian agent sent to Chechnya in the 1990s. He believed he was "fighting terrorism" - but he was startled by what he found. For him, the turning point was when he arrested a sixteen year-old "resistance fighter". He told the boy he should be at school. "I want to be," the boy said, "but my school was blown up." Litvinenko began to speak out against the assault on Chechnya - and had to run for his life, to London, where he became a British citizen. His food was spiked with nuclear material in a restaurant in Central London, and he died in agony, of radiation poisoning. The trail of nuclear material ran quite literally through British Airways planes - back to Moscow.
"Alexander knew who killed him," Zakayev tells me, adding that he was with Litvinenko as he lay dying, "right to the end." But despite extensive, documented claims, this suspect has not been charged, and the Kremlin has refused Britain's extradition requests. "Indeed, he is a member of the Russian Parliament, and celebrated by Putin," Zakayev says.
Europe allowed a Russian dissident to be murdered without consequences - so it is happening again. Umar Israilov was a 27 year-old bodyguard to Ramzan Kadyrov, the thug appointed by Putin to run Chechnya today, who describes the province as a "zoo" filled with "animals", and brags "I will be killing as long as I live." Israilov was horrified, so he fled to Austria, to speak out. He begged the Viennese police for protection, but they refused. On Jaunary 13th this year, he was chased through the streets of Vienna by a gang of hitmen - and shot twice in the head.
This is only going to get worse. Dissent in Russia was relatively low as the economy boomed, built on a swelling oil-price. But now Russia's stock market has fallen by 75 percent since last summer, the biggest drop in the world. That's why the ex-KGB chairman of the Duma's Security Committee, Gennaday Gudkov, says: "We are expecting mass unemployment and mass riots."
To prepare, Putin has restored the Soviet-era criminalisation of dissent. Now, if you "advise" a human rights organisation - merely by speaking to them - you are guilty of "high treason." More people are going to flee to Europe - and we are going to have to choose between protecting them, or letting them be picked off on our streets.
Yet for Europe, human rights in Russia are a bitterly low priority. Our governments are partly responsible for this resurgence of dictatorship. After the fall of Soviet tyranny, it was Europe and the US that forced Russia's infant democracy to privatize everything overnight in a programme of "shock therapy." The social services were shut down overnight, and everything flogged off. As a result, the country's assets were seized by piratical oligarchs, and - according to a major study by the Lancet - over a million ordinary Russians died of cold or hunger or extreme poverty. This chaos and mass death made the old anti-democratic propaganda seem true - and sent the population running back to the old, cold face of dictatorship.
Worse still, we in Europe are addicted to Russia's gas supplies. If we anger Putin, he can turn off the gas taps, as he has shown with his bullying of Ukraine. Our government has made the bleak calculation that a dissident being murdered in central London doesn't weigh much against keeping the lights on. There are many urgent reasons to end our dependence on fossil fuels. One of the most compelling is that, until we do, we will not be able to keep a democratic space for Russian dissidents to speak the truth, even here, on our own soil.
Zakayev looks out of the window, across the London skyline. "I do not want to die. Alexander and Anna did not want to die. But for the hundreds of my friends who are gone, I have to keep speaking." We - the peoples of Europe - have to protect that right, at least, and at last.
Johann Hari is a writer for the Independent. To read more of his articles, click here.