LONDON — When it comes to relations with Vladimir Putin’s Russia, Mikhail Khodorkovsky has blunt advice for Europe: Wake up — and stop playing nice.

The former billionaire chief of Yukos Oil, once Russia’s richest man, spent 10 years in prison on fraud and tax evasion charges that were widely viewed as political retribution by the Kremlin, and now marshals opposition forces through his democracy and human rights organization Open Russia. He says European leaders are naïve to think it is possible to negotiate with Putin’s Kremlin, and that any easing of economic sanctions would be a grave mistake.

Putin will never change his ways and the EU’s foreign policy chief, Federica Mogherini, and other EU leaders should recognize they have been trying in vain to pacify the Russian aggressor, he said in an interview in London, where he now lives.

“I’d like to explain to them, saying: 'Guys, do you understand why we call today’s regime in Russia not only kleptocratic — it’s clear why it is kleptocratic — we call it mafia-style because those are people with criminal thinking.'”

In dealing with Moscow, Mogherini should seek advice from a cop in some not-so-safe area of her native Italy "where they deal with real hooligans and bandits," Khodorkovsky said. “How should you communicate with a bandit so he won’t punch you in the face again? The policeman will tell you that the worst you can do is to tell him: ‘You are doing a bad thing, but I am ready to cooperate.’ Policemen call it 'playing the victim.’”

At the time of his arrest in 2003, Khodorkovsky had long been viewed as a threat to the Kremlin and the seizure of his company was a warning to other oligarchs. Putin abruptly pardoned him on “humanitarian grounds” in December 2013, just before the Winter Olympics in Sochi. Released from a penal colony in northern Russia, he was flown by private jet to Germany.

These days, he looks the part of think-tank chief, rather than a captain of industry, with rimless eyeglasses and small paunch, wearing jeans and a blazer and carrying a small black valise. He's still rumored to be worth hundreds of millions, though much of his fortune remains locked up in a dispute between the Russian government and former shareholders of Yukos like himself.

For a brief time after his release, in Switzerland, he felt he was being followed. But in London, where his office in Hanover Square has tight security, Khodorkovsky said he generally feels safe. During the interview, he kept his iPhone and laptop open in front of him, and every once in a while was distracted by messages popping on screen.

'Can it get any worse?'

Open Russia convened Russia specialists, MEPs and policy experts in Brussels last week for the second annual Boris Nemtsov Forum, named for the opposition leader who was murdered on a bridge just outside the Kremlin walls in 2015. The men charged with his murder, now on trial, are Chechens, some with links to the security services of the Chechen leader, Ramzan Kadyrov, who considers Putin a second father.

Khodorkovsky said Kadyrov and Putin were ultimately responsible for Nemtsov’s death, one way or another, even if they didn't necessarily order his murder. “We can say that Kadyrov is a criminal, Putin is a criminal,” he said, adding that the crime remained problematic for Putin "because it is a breach of his real authority. When the state loses the monopoly on violence, you understand, it is undermining.”

The main theme of the Nemtsov conference — preparing for the post-Putin era — appears somewhat distant given more pressing challenges, such as Russia’s role in Syria and the failure of the Minsk 2 peace deal in eastern Ukraine.

At an EU summit last month, leaders discussed Russia at the request of Italy's Prime Minister Matteo Renzi, who wants an end to economic sanctions imposed on Russia for its annexation of Crimea. Instead, the Kremlin’s role in bombing Aleppo and its support for Syrian President Bashar al-Assad dominated the conversation.

Khodorkovsky said EU leaders must understand that relations with Russia could not get worse, and will not get any better until Putin is out of office. European officials are making a mistake by not doing more to encourage Russia’s liberal opposition for fear of antagonizing Putin, he said.

“I’m very surprised,” he said. “What are they afraid of? Can relations with Putin be worse than they are today?” Putin has deployed nuclear missiles in Kaliningrad and menaced the Baltic states, Khodorkovsky said, adding: “Whatever he could do to ruin relations with Europe, he has already done.”

Waiting to reach out to the opposition until Putin is gone could be a mistake. “I am surprised by the logic of the European diplomats,” he said. “'When there will be someone after Putin, we will speak.’ Guys, but will someone speak to you? Maybe then there will be no one to talk to.”

Khodorkovsky is often mentioned as a post-Putin candidate for president. It remains to be seen if he will ever return to Russia, let alone jump back into politics. But Vladimir Kara-Murza, an opposition figure who is now working as national coordinator of Open Russia, said Khodorkovsky was playing an important role by uniting opposition forces.

“This is one of the most successful managers in Russian history,” Kara-Murza, who nearly died of a suspicious illness in May 2015, in what he and other opposition leaders believe was a failed assassination attempt by poisoning.

Political upheaval in Russia typically comes without prior notice, whether in 1917 or 1991, said Kara-Murza.

“Nobody was prepared,” he said. “The next time political change comes to Russia, I venture to say it will again be quick and unexpected.” Khodorkovsky, he said, was working to prepare people for it, including in the West.

Nobody to blame

The forum last week at the European Parliament coincided with a Russian Supreme Court ruling overturning the conviction of opposition leader Aleksei Navalny on corruption charges that were widely viewed as trumped up and politically motivated. This temporarily clears him to run for public office, potentially as a challenger to Putin in the next presidential race.

But Dmitry Gudkov, the sole opposition member left in the State Duma, Russia’s lower house, until he was voted out of office in September's parliamentary elections, said the Kremlin had allowed the conviction to be overturned so that it could use Navalny to legitimize the next election, which Putin will win in any event because of his control of virtually all state media and resources.

“The Kremlin needs somebody to make it more competitive,” Gudkov said. “Navalny could be this option."

Donald Trump’s unexpected win in the U.S. presidential election presented a challenge for Putin because it proved the American system to be fair and legitimate in the eyes of the Russian public — with unexpected outcomes possible, said Gudkov. With Trump about to move into the White House, “there is nobody to blame for all of Russia’s problems now.”

Khodorkovsky broadly shared the belief that Putin — or one of his political operatives — had some use for Navalny, who will now face a retrial on corruption charges.

“There is a reason why they need him," he said, adding that Navalny might prove to be "a tool in a fight between the elites," or be used as some form of political bait.