"Russian mafia-like groups" could have been behind poisoning of former spy, Jeremy Corbyn suggests

"Russian mafia-like groups" living in Britain could have been behind the poisoning of a former double agent, Jeremy Corbyn has suggested.

The Labour leader also warned the UK Government not to "rush way ahead of the evidence" by assuming that the Kremlin sanctioned the attack on Sergei Skripal and his daughter, Yulia, in Salisbury.

Corbyn's remarks, in an article for The Guardian, appeared to row back on comments he made yesterday afternoon when he said "all the evidence points towards" Russia being to blame for what happened.

They are also likely to further infuriate Labour MPs who have criticised the party leader for not explicitly blaming Vladimir Putin's regime for the poisoning, which has also left a police officer seriously ill.

In his article, Corbyn said: "Theresa May was right on Monday to identify two possibilities for the source of the attack in Salisbury, given that the nerve agent used has been identified as of original Russian manufacture.

"Either this was a crime authored by the Russian state; or that state has allowed these deadly toxins to slip out of the control it has an obligation to exercise. If the latter, a connection to Russian mafia-like groups that have been allowed to gain a toehold in Britain cannot be excluded."

He also said: "The use of military nerve agents on the streets of Britain is barbaric and beyond reckless. This horrific event demands first of all the most thorough and painstaking criminal investigation, conducted by our police and security services.

"They have a right to expect full support in their work, just as the public should also be able to expect calm heads and a measured response from their political leaders. To rush way ahead of the evidence being gathered by the police, in a fevered parliamentary atmosphere, serves neither justice nor our national security."

Corbyn also warned against a "McCarthyite intolerance of dissent" of anyone who suggests a cautious approach to handling the crisis.

"Instead, Britain needs to uphold its laws and its values without reservation," he said. "And those should be allied to a foreign policy that uses every opportunity to reduce tensions and conflict wherever possible."

But Labour MP John Woodcock, who has criticised Corbyn's approach to the Salisbury attack, said: "There is much in this piece which is troubling, not least the strange reference to McCarthy-ism.

"Jeremy Corbyn is not a powerless victim, he is a man who seeks to lead our country at a time when it has been shown to be under significant threat."