A British financier and arch critic of Vladimir Putin has been placed under criminal investigation in Russia over a "trumped up" allegation that he was behind the poisoning of a whistleblower who collapsed and died in Surrey.

Bill Browder, who has led a campaign against Putin’s regime, is being investigated for murder by a committee within Russia’s interior ministry. The committee is run by a former classmate of Mr Putin.

The inquiry was opened in December, four days after Mr Browder succeeded in persuading the European Union to adopt powerful legislation that allows authorities to bring sanctions against corrupt Russian officials.

In retaliation, Mr Browder was accused of orchestrating the murder of Alexander Perepilichnyy, a Russian businessman who had fled to the UK and handed documents detailing high level corruption to Mr Browder.

Mr Perepilichnyy, who had been subjected to Kremlin death threats, collapsed and died after going for a jog. There have been suggestions that he was poisoned with gelsemium elegans, a plant toxin used by Russian and Chinese assassins.

Mr Browder, who has joint US and UK citizenship, was the first person to flag up to Surrey police that Mr Perepilichnyy might have been murdered.

Mr Browder said: “Putin has completely lost the plot and is throwing absurd murder accusations at me like they were candy. His officials don’t even bother to try to make the allegations look credible any more.”