The European Court of Human Rights has found Russia guilty of Alexander Litvinenko’s murder in 2006.
Litvinenko had been a Russian spy, but had gone to live in England after accusing his masters of ordering the murder of Boris Berezovsky.
He had also authored two books criticising his country, as well as accusing Russian President Vladimir Putin of ordering the death of Russian journalist Anna Politkovskaya.
In 2006 Litvinenko had felt unwell and was taken to hospital, where it resulted he had been poisoned with Polonium-2010, a radioactive material. He had died after 22 days in agony.
A public inquiry in the UK in 2016 had concluded the murder had probably been approved by President Putin.
The inquiry also found that two Russian nationals, Andrei Lugovoi and Dmitry Kovtun, had placed the radioactive substance in a drink consumed by Litvinenko.
Russia had always denied involvement in this crime and the two Russians who according to the inquiry had killed him, had likewise denied their involvement.