Alexei Navalny aide says his survival may depend on value to Vladimir Putin

Leonid Volkov warns Russian opposition leader's health is at risk from indefinite solitary confinement

Alexei Navalny's survival may depend on his value to Vladimir Putin as a future bargaining chip, his chief aide said, warning that the opposition leader's health was at risk after being forced into indefinite solitary confinement.

Leonid Volkov, speaking on a visit to London, added that Navalny had lost access to his family and was being permanently detained in a 8 by 12ft" cell following the isolation decision by Russian authorities last week.