With a British citizen fighting for his life in hospital after a suspected Russian nerve agent attack, Jeremy Corbyn, the leader of the opposition Labour Party, was under pressure Thursday to confront Moscow over the apparent attack.
Senior Labour politicians including the party's defence spokeswoman,Nia Griffiths, broke ranks with Mr Corbyn to declare Russian "unequivocably responsible" for the March 4 incident in which Sergei Skripal and his daughter Yulia where found comatose on a bench in Salisbury. “We are fully supportive of the Government’s actions, because clearly we accept that the Prime Minister has said that Russia is responsible,” Mrs Griffiths said.
Theresa May, the British prime minister, said the pair were attacked with Novichok, a military grade nerve agent developed by the Soviet Union.
Speaking in the House of Commons, Mr Corbyn struck the wrong tone by closely questioning why the government had not handed over the material to Russia as Moscow requests. His spokesman compounded anger at Labour's leadership by querying intelligence findings issued by the British state over decades.
Mr Corbyn's response to the crisis appeared on Thursday to have shattered the truce reached with centrist MPs since the party revived its support in last year's general election.
The Russian angle is a proven political weak spot for the veteran leftist who recently accused by a Conservative lawmaker -- who later retracted the claim -- of passing secrets to a Czechoslovak agents he met in the 1980s.
Anger at his failures came from internal rivals, including former cabinet minister Ben Bradshaw who told parliament that "most of us on these benches fully support the measures she has announced."
Colleague Yvette Cooper demanded "unequivocal" condemnation while former Labour minister Pat McFadden said defending Britain when threatened was an "essential component of political leadership".
About 20 Labour backbenchers signed a motion stating the Commons "unequivocally accepts the Russian state's culpability".
In the media, the Daily Telegraph denounced Mr Corbyn's "craven posturing".
Even the Left-wing Guardian sounded several notes of dismay. "May made to look like a political colossus as Corbyn refuses to believe in Russian involvement," read the headline for its parliamentary sketch.
"He sounded too keen to find another explanation," said its editorial.
The right-wing Daily Mail splashed on the headline: "Kremlin Stooge".
Mr Corbyn's spokesman and strategist Seumas Milne is a controversial pro-Russian activist and writer. It was he who later doubted the findings of Britain's intelligence services.
"There is a history between weapons of mass destruction and intelligence which is problematic, to put it mildly," he said.
Mr Milne's appointment in 2015 raised eyebrows given previous opinion articles he had written in the Guardian, in which he said "Putin has now become a cartoon villain and Russia the target of almost uniformly belligerent propaganda across the western media."
Centrist Labour MP Chuka Umunna tweeted that "Milne's comments do not represent the views of the majority of our voters, members or MPs."
Long-time ally and shadow interior minister Diane Abbott defended her boss.
"If we are to persuade any other nation to take significant measures alongside us, they may ask for a higher burden of proof," she said.