Boris Johnson's criticism of Jeremy Corbyn over Labour's response to the Salisbury nerve agent attack is "not at all helpful", one of the foreign secretary's own junior ministers has said.
Mark Field, a Foreign Office minister, criticised Mr Johnson for calling the Labour leader Moscow's "useful idiot" and suggesting he had given Moscow "false credibility" by refusing to unequivally blame Vladimir Putin's regime for the poisoning of Sergei and Yulia Skripal.
The foreign secretary used an article in The Sunday Times to renew his attack on Mr Corbyn, who he said was playing "Putin's game" and "shames himself" by giving credence to Russia's claims.
Mr Field told the BBC's Westminster Hour: "We all know Boris has a style and there's also a style that the rules of ordinary political gravity don't apply to Boris Johnson - he gets away with his style."
Responding to the comments about Mr Corbyn, he said: "I would always try and play the ball and not the man when it comes to these things.
"I think to get personal about it is not helpful at all."
In his article, Mr Johnson wrote or the Mr Corbyn: “Even now he cannot bring himself unequivocally to say that the Russian state was responsible. Every time he allows himself to speak freely he reverts to his comfort zone, his infantile leftist background of sympathy for any country, any movement, however unappealing, that is hostile to Britain.”
“I will not mince words: this is cynical nonsense and Corbyn shames himself by lending it succour. Truly he is the Kremlin’s useful idiot.”
He added: "There is only one thing that gives the Kremlin succour and lends false credibility to its propaganda onslaught. That is when politicians from the targeted countries join in.
"Sadly, I am driven to the conclusion that Jeremy Corbyn has joined this effort."
Mr Corbyn faced criticism over his response to the Salisbury attack after he demanded further evidence Russia was responsible and questioned the abilities of the UK security services.
However, Labour has claimed its caution was vindicated in recent days, when government scientists at the Porton Down research laboratory admitted they had been able to confirm the source of the novichok agent used in the poisoning.
Mr Johnson faced questions over his previous suggestion that Porton Down had told him there was "no doubt" over the source of the agent - a claim that now appears to have been inaccurate.
A Labour spokesperson said Mr Johnson had "made a fool of himself and undermined the Government" with his latest comments, adding: “Jeremy Corbyn has repeatedly said the evidence points to Russia being responsible, directly or indirectly, and that the Russian authorities must be held to account on the basis of evidence.”
But other senior conservatives backed the foreign secretary. Sajid Javid, the housing and communities secretary, told the BBC's Andrew Marr Show: "There’s no doubt when it comes up against this issue with Russia that we are having, this very serious issue, that Jeremy Corbyn has let the British people down.”
Sergei Skripal, 66, and his 33-year-old daughter Yulia were found unconscious a park bench in Salisbury on 4 March.
Following confirmation they had been poisoning with a novichok nerve agent, the UK government blamed Russia for the attack and announced a new of spate sanctions against Moscow, including the expulsion of 23 diplomats. Russia has denied being responsible.
On Saturday, the Russian Embassy in the UK said its ambassador had requested a meeting with Mr Johnson to discuss the case and called recent communications "utterly unsatisfactory". It expressed hope the UK would "engage constructively" with the request, but the Foreign Office dismissed the move as a "diversionary tactic".
Mr Skipal is said to no longer be in a critical condition and his daughter has said she is "growing stronger by the day". The Foreign Office says they are both likely to have "ongoing medical needs".
