Mikhail Khodorkovsky, a former tycoon and opponent of Vladimir Putin, is released from prison in north western Russia after ten years inside.
Mr Putin surprised Russians and cheered the business community by announcing on Thursday that he would release a man he has long reviled because Mr Khodorkovsky’s mother was ill.
Russia’s federal prison service said Mr Khodorkovsky was heading for Germany following his release and that his mother, Marina, was undergoing medical treatment there. A German police official said he was en route to Berlin and was expected to land on Friday afternoon.
The move is widely seen as a gesture to critics of his human rights record before Russia hosts the Winter Olympics at Sochi in February.
A decree signed by Mr Putin and distributed by the Kremlin took immediate effect. Its wording described the decision to pardon the 50-year-old Mr Khodorkovsky, once the richest man in Russia, as having been “guided by the principles of humanity”.
Putin had said at the end of a four-hour annual news conference on Thursday that Mr Khodorkovsky asked for clemency.
The surprise announcement followed his announcement that two members of the Pussy Riot protest group would also be freed, under an amnesty passed by parliament this week.
Mr Khodorkovsky has been in jail since he was arrested in 2003 in what supporters say was part of a Kremlin campaign to punish him for political challenges to Putin, gain control of his oil assets and warn other tycoons to toe the line.
The oil baron fell out with Putin before his arrest as the president clipped the wings of wealthy “oligarchs” who had become powerful during the chaotic years of Boris Yeltsin’s rule following the collapse of Soviet communism.
His company, Yukos, was broken up and sold off, mainly into state hands, following his arrest at gunpoint on an airport runway in Siberia on fraud and tax evasion charges.
He became a symbol of what investors say is the Kremlin’s abuse of the courts for political ends.
The Kremlin denies this but Mr Putin has singled Mr Khodorkovsky out for bitter personal attacks and ignored many calls for his release.
Within hours of his release Mr Khodorkovsky issued a statement confirming that he had sought a pardon from Mr Putin for family reasons and had not admitted guilt on the fraud charges.
“The issue of an admission of guilt was not raised,” he revealed.
“I am very eager for the moment when I can hug my loved ones,” he said. “I will welcome the opportunity to celebrate this upcoming holiday season with my family.”
His mother Marina, said: “I want to just hug him. I don’t even know yet what I am going to say to him.” Her son said last month that she was facing a second bout of cancer and he might not see her again.
A Russian government source said the pardons would deprive Western critics of a cause: “I think the decision to free Pussy Riot and Mr Khodorkovsky was taken just before the Olympic Games so that they will not be able to wield this banner against Putin.”
On a website supporting Mr Khodorkovsky, a man named Igor commented: “It was simply beneficial for Putin to make a show of ‘mercy’ before the Olympics in order to avoid a huge world scandal.”