Jeremy Corbyn has been mocked by own MPs after saying Russia should be given a sample of the nerve agent used in the Salisbury attack so it can "say categorically one way or the other" whether it is responsible.

The Labour leader also said he would be happy to work with President Putin if he was Prime Minister and stopped short of blaming the Kremlin for the attack, despite his deputy John McDonnell doing so over the weekend.

It exposes a deepening split in the party's position on the nerve agent attack which has left Sergei Skripal and his daughter Yulia in a coma in hospital.

Last week Mr Corbyn was criticised for refusing to categorically blame Russia for the Novichok poisoning and his communications chief drew further ire when he claimed British intelligence cannot be trusted after the Iraq war dossier.

Responding to his latest remarks on the issue Mr Corbyn was roundly mocked by his own MPs including Ian Austin, a member of the Foreign Affairs select committee, who joked that Mr Putin would never accuse himself of having smuggled the nerve agent into the UK to use against the former spy.

He said: "Does anyone seriously think Putin will say: ‘Thanks for the sample. We have now examined it and yes, I'm sorry to say that it did come from Russia and was then given to one of our agents to murder Mr Skripal in the way we have murdered lots of other opponents’? Who thinks that?”