Navalny, who staged massive anti-Kremlin protests as President Vladimir Putin's fiercest foe, died in the Arctic penal colony in February 2024.

La rivelazione sulla fine dell’oppositore di Putin, morto in una colonia penale in Siberia

There is no innocent explanation for the toxin, called epibatidine, being found in samples taken from Navalny's body, the Foreign Office said.