麻豆约拍

The German chancellor, Angela Merkel, has urged Russia to carry out a full investigation after doctors in Berlin confirmed that opposition leader, Alexei Navalny, was poisoned.

The hospital in the German capital said his condition was not currently life-threatening, but long-term damage to his nervous system could not be ruled out.

Mrs Merkel said those behind the poisoning must be held accountable. But what power do western leaders have to stand up to Vladimir Putin?

Bill Browder is a critic of President Putin. He successfully lobbied US politicians to pass the Magnitsky Act, which allows the US to sanction overseas officials guilty of human rights abuses.

(Photo: Russian opposition leader Alexei Navalny. Credit: Getty Images)