THE FOREIGN Secretary has urged Russia to conduct a criminal probe into the poisoning of Putin's biggest rival.

Dominic Raab summoned the Russian Ambassador to the Foreign, Commonwealth and Development Office (FCDO) today to express his concern about Alexei Navalny's alleged poisoning with Novichok.

The 44-year-old has been taken out of an induced coma and is said to be responding to speech at the Berlin hospital where he has been treated since last month.

Mr Raab is said to have told Andrei Kelin the Russian ambassador to the UK, that the use of the banned chemical nerve agent is absolutely unacceptable, and Russia must answer for the actions.

The FCDO has confirmed it will be working to "hold the perpetrators to account" along with international partners.

A Foreign, Commonwealth and Development Office spokesman said: “Today the Russian Ambassador to the UK was summoned to the Foreign, Commonwealth and Development Office.

"The UK Government registered its deep concern with the Russian Government about the poisoning of Alexey Navalny with a chemical nerve agent from the Novichok group.

“The Foreign Secretary has made it clear that it is absolutely unacceptable that a banned chemical weapon has been used, and that violence has again been directed against a leading Russian opposition figure. "There is a case here for Russia to answer. This took place on Russian soil, against a Russian citizen.

"They have international obligations to uphold.

"This is nothing short of an attack against the rules based international system which keeps our societies safe.

“Russia needs to conduct a full, transparent criminal investigation into Mr Navalny’s poisoning. We will work with our partners, including through action in the OPCW, to hold the perpetrators to account.”