Foreign Secretary David Cameron said:
The politically motivated conviction of Vladimir Kara-Murza is deplorable. Imprisoned on false charges by the Russian regime, Mr Kara-Murza is being persecuted for his anti-war stance and defence of human rights.
It was an honour to meet Evgenia Kara-Murza and Elena Gordon, who have worked tirelessly to raise awareness of their husband's and son's case.
The conditions in the Omsk penal colony are threatening Mr Kara-Murza's life and his health is deteriorating. He must be released on humanitarian grounds for urgent medical treatment.
Through diplomatic interventions at the highest levels, financial sanctions targeted at those behind his poisoning and imprisonment, and by raising his case on the international stage, we are sending a clear message that the UK will not stand for this abhorrent treatment of one of our citizens.
Russia's depraved treatment of political prisoners must end.
