The mother of Vladimir Kara-Murza, a British-Russian anti-Putin activist, has been taken to hospital in Berlin after a suspected poisoning.

Elena Gordon was brought to an isolation ward at the Charité hospital in Berlin on Tuesday evening after telling police she believed she had been poisoned, German media reported.

Police said they were investigating on suspicion of attempted murder and that Ms Gordon’s “blood, clothing and apartment” were being checked.

“The police are taking all necessary measures to ensure public security and to investigate potential suspects,” the force said.