Russia is responsible for the assassination of Alexander Litvinenko, ruled the European Court of Human Rights (ECHR).
Former Russian spy Mr Litvinenko died after being poisoned by a rare radioactive substance in London in 2006.
A statement on the court’s decision on Tuesday said: “Russia is responsible for the assassination of Aleksandr Litvinenko in the UK.”
Russia has always denied any involvement in his death.
The case was brought by his widow Marina Litvinenko, who had sworn to obtain justice for her husband and to sue the Kremlin in international courts.
A public inquiry concluded in 2016 that the assassination of Mr Litvinenko – a vocal critic of Vladimir Putin – who died after drinking tea containing radioactive polonium-210 – was “probably” carried out with the approval of the Russian president.
Led by former High Court Judge Sir Robert Owen, the investigation found that two Russian men – Andrei Lugovoi and Dmitri Kovtun – had deliberately poisoned Mr Litvinenko by putting polonium-210 in his drink at a London hotel , resulting in an excruciating death.
He said the use of the radioactive substance – which could only have come from a nuclear reactor – was a “strong indicator” of state involvement and that the two men likely acted under the direction of the service. Russian security agency the FSB – which Mr. Litvinenko worked for, as well as the KGB.
Possible motives included Mr Litvinenko’s work for British intelligence agencies after fleeing Russia, his criticism of the FSB and his association with other Russian dissidents, while claiming there was also a “personal dimension” to the antagonism between him and Mr. Putin.
The statement on the European Court’s decision added: “The Court concluded in particular that there was strong prima facie evidence that, in poisoning Mr. Litvinenko, Mr. Lugovoy and Mr. Kovtun had acted as agents of the Russian state. She noted that the government had not provided any other satisfactory and convincing explanation of the events or contradicted the findings of the UK inquiry.