“Novichok” and “Solsberi” leaped to the top of Russian propaganda broadcasts overnight, as pro-Kremlin media seized on an admission that British scientists had been unable to identify the “precise source” of the nerve agent used against former spy Sergei Skripal and his daughter Yulia.

“Have you no shame, Theresa?” thundered headlines on the country’s main news network on Wednesday morning. The revelation from the Portland Down military laboratory was a slap in the face for the British, presenters suggested — and now the prime minister will find it impossible to maintain a European alliance.

“Theresa May has to prove the basis of accusations or she needs to step down,” they said.

Throughout the day, state news interspersed PMQ interventions by the Labour leader Jeremy Corbyn with gleeful comments by President Putin, who was speaking on the matter for only the second time.

“The speed of the anti-Russian campaign has been bewildering,” said Mr Putin. “Scotland Yard had declared they needed no less than two months for a full investigation...”

In reporting the Portland Down admission, there was no mention of earlier narratives that linked the laboratory to the poisoning itself. Likewise, few publications reported the entirety of comments made by the chief executive Gary Aikenhead. His surprising assertion that it was never the intention to ascertain the country of origin was all too easily cut – no doubt, much to the chagrin of the British government.

On Wednesday, the head of Russia’s Foreign Intelligence Service Sergei Naryshkin described the Skripal case as a “grotesque provocation” by American and British spy agencies. He went on to compare the current confrontation to the Cuban Missile Crisis of 1962, the nearest the Soviet Union and the US came to nuclear war.

“We need to stop raising stakes irresponsibly, and projecting power on to interstate relations to avoid a new crisis,” he said.

Whatever Mr Aitkenhead had intended to say with his much-spun comments, they have laid bare some of the weaknesses in the official British position.

Using a formula of “capability, intent and motive” the UK has said it is “highly likely” that Russia was responsible for the Salisbury attack. Questions persist over each part of that formula.

An investigation by Russian independent media has already shown that novichok stocks were sold to organised criminals in the 1990s – indicating groups other than the state theoretically have the capacity to kill using such a nerve agent.

A widely mistranslated phrase, allegedly uttered by the Russian president – “traitors will kick the bucket” – is regularly used to justify the second strand of the allegation, intent. Mr Putin actually said “traitors will kick the bucket without our help”. The Kremlin has formally denied having an assassination list.

The third leg of the troika, motive, has puzzled many experts from the start. Mr Skripal was not, apparently, actively collaborating with British security services, and had been pardoned during the spy swap. While the British ultimatum played into Mr Putin’s election campaign, it was not clear at the time that this would be so.

The existence of additional intelligence material has been broadly hinted at by the British side. It was as much as confirmed in statements by the US ambassador to Moscow, John Huntsman, last week. Downing Street will now face increased pressure to make some of its more sensitive information public.

Meanwhile, Russia today hopes to extend its PR victory at an extraordinary meeting of the Organisation for the Prohibition of Chemical Weapons in the Hague. The meeting, convened by Russia, is being held behind closed doors, with a statement is expected about 5pm British time.