Khodorkovsky's mother: 'Contempt' for Kremlin
Moscow's Leningradsky Vokzal is the best known railway station in Russia.
It is the terminus where the heroine of Leo Tolstoy's 19th Century novel Anna Karenina watches a man being cut in two by a train - a warning of the tragedy to come.
Today the station is still a busy place, with long-distance trains setting off for St Petersburg and the Arctic.
This month, on a Tuesday night, well after midnight, an elderly woman made her way through the crowds and bustle to board the "Arktika" express to Murmansk. It was the start of a long journey in a two-bed sleeper compartment.
Marina Khodorkovskaya was not heading for Murmansk. She was planning to alight a few stops earlier at Segezha - a scruffy town close to the Arctic Circle, known for its pulp and paper factory and for the gulag of the Stalin era.
These days there is still a prison in Segezha - Penal Colony No 7.
That is where Mrs Khodorkovskaya was heading to visit her son Mikhail Khodorkovsky, once Russia's richest man, and now seen by many as its longest serving political prisoner.
She makes the journey every three months, and this month she agreed that we could travel with her.
She told me she had lost count of the number of times over the last 10 years that she had made the journey either to Segezha or to Eastern Siberia where her son use to be held.
"I used to collect tickets," she recalled. "But then I threw them all away."
When she described the visiting room, it sounded more suited to violent criminals than those convicted of economic crimes.
"It is a long room divided into two with prisoners on one side and relatives on the other," she explained. "Then there are partitions - each with a little desk and a phone set on either of the thick glass. If somebody talks loudly next to you, you can hardly hear anything."
The journey to Segezha takes 20 hours in each direction. The three-monthly visits last four hours.
Mikhail Khodorkovsky is also allowed a 15-minute weekly phone call from a booth outside.
"It's very cold there in winter," Mrs Khodorkovskaya said. "Once we thought he was ill, because he was speaking very strangely. But it turned out that his lips were frozen, and he couldn't speak with his normal voice."
Khodorkovsky was a billionaire who made his money in the 1990s by building Russia's biggest oil company Yukos.
When Vladimir Putin became president he told the oligarchs to stay out of politics, but in 2003 Khodorkovsky started challenging that, pushing back against the increasing authoritarianism and - according to some ministers of the time - buying influence in the Duma.
Eventually he was arrested and put on trial for tax evasion and fraud.
There is little doubt that some of his business practices in the 1990s had been questionable.
The pro-Putin Duma deputy Vyacheslav Nikonov told me: "I don't consider Khodorkovsky to be a political prisoner. He got what he deserved according to the Russian criminal code. There is no-one saying that he paid his due share of taxes."
But no other oligarch was put on trial, and when Khodorkovsky's eight year sentence was drawing to a close he was put on trial again and given a further six years in prison.
The US and EU called it "selective justice." The Russian opposition insists he is a "political prisoner", and it is hard to argue with that.
As the seemingly endless birch forests and lakes of northern Russia trundled past the window of the "Arktika" express, I asked Mrs Khodorkovskaya if she still got angry.
"You know, it's not anger", she replied.
"It's contempt - contempt towards people who are ready to destroy the lives of people, and their wives and children, just for money. Lives destroyed, and why? Only because of money."
We were not able to go in with Mrs Khodorkovsky to visit her son.
The colony's governor told me to my face that if the BBC team came within 50m of the prison we would be arrested.
But what we saw from the road is a dilapidated compound surrounded by rusting barbed-wire fences and guard dogs.
Giant spotlights can be seen on top of some of the buildings, and all around the perimeter stand wooden watchtowers strangely reminiscent of a World War II movie. It is not a high-tech prison, but it is strangely intimidating.
Khodorkovsky's incarceration has become relevant this year, partly because it is his 10th year in prison, but also because there has been an acceleration recently of what seem to be "political trials."
Amnesty International has declared two imprisoned women from the punk protest group Pussy Riot to be "prisoners of conscience".
A group of street protesters who demonstrated on the day before President Putin's inauguration have been in jail for almost a year, and are still awaiting trial.
The most charismatic leader to emerge from the new opposition, Alexei Navalny, is on trial for embezzlement - in what he claims is a political prosecution. The maximum prison sentence he faces is 10 years.
Ahead of her visit Marina Khodorkovskaya agreed to ask her son a question on our behalf. What were his thoughts about those standing trial today?
Through his mother, Khodorkovsky sent his reply.
"Because our courts are unfair, it is hard to stay strong. But people need to be honest, tell the truth and speak out. They should not be afraid."