On the second anniversary of his death, Lyudmila Navalnaya says her son did not "simply die in prison".

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

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