Theresa May has never published her case blaming Russia for the Salisbury poisoning. She has reason to be wary of Blair-style intelligence dossiers, and she didn’t need to make everything public to win the support of allies. But as things stand, her case against Russia is open to misinterpretation by the Kremlin. As we have seen with this morning’s headlines.

Yesterday, Sky News interviewed Gary Aitkenhead, chief executive of Porton Down, who said:

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“We were able to identify it as Novichok, to identify it was a military-grade nerve agent. We have not verified the precise source, but we have provided the scientific information to the government, who have then used a number of other sources to piece together the conclusions that they have come to.”

His confirmation that they have “not verified the precise source” was more information than the government has so far offered on the record, therefore it was news. The British press referred to it as an “admission”. The German press followed it up, and suddenly, worldwide, it looks like doubt is being cast on the whole affair. Political reaction followed. One of Merkel’s allies starts to ask why Russian diplomats are being expelled if we’re not certain the Novichok came from Russia. This all delights Putin, who sought to ramp up the uncertainty: last night he expressed his “bewilderment” against this baseless “anti-Russia campaign” and called for an inquiry. Confusion! Mission accomplished.

Poor old Mr Aitkenhead is being criticised for bad “presentation” by unnamed government ministers. But this isn’t entirely fair. He runs a science plant, he’s no spin doctor: he spoke the truth. What he said was only a story because the government has not been as forthcoming. No one has ever claimed, on or off the record, that the Novichok has been traced to Russia by lab tests – indeed, the government has always made clear to allies that geo-tracing had not been possible. Sometimes it is. The polonium-210 used by former KGB agents to kill Alexander Litvinenko was traced back to a specific Russian lab. The poison used against Skripal has been identified as one of four known strains of the Novichok, A234, but there’s no means of telling where it was made.

As I said in my Daily Telegraph column, the government shared with allies raw data from the medical tests to demonstrate why they thought it was Novichok. It then admitted that skills to produce Novichok are possessed by several countries – the potentially hostile ones being Iran, North Korea, China and Russia. At this point, science gives way to old-fashioned dot-joining. Could it be the Russian mafia? They hate publicity and when they want someone dead they make it look like suicide or a mugging. Given how difficult nerve agent is to transport and deploy, it had to be a government actor. So you need to ask what motive would the other countries have in going to such lengths (and risks) to frame Russia. There’s no answer. If anything, this suits Putin underlining his ability to embarrass the West.

It was an intelligence assessment, but hardly a difficult one. Does the Salisbury poisoning fit a pattern of behaviour? Yes. Does it fit Putin’s strategy? Yes. Is there another plausible explanation? No. Is it time for the West to respond? That question was answered with the diplomatic expulsions last week.

So there is no crack in Theresa May’s case against Russia, but some poorly-judged media handling has given the Kremlin enough ammunition to claim otherwise.