Boris Johnson is facing embarrassing questions over his claims that #Russia had produced the Salisbury nerve agent after it emerged that the Foreign Office had deleted a tweet blaming Moscow for the attack.
With the foreign secretary already under pressure over his remarks two weeks ago that a Porton Down scientist had been “absolutely categorical” that the novichok had originated in the country, Jeremy Corbyn accused Johnson of “completely exceeding the information he had been given” after the emergence of the deleted tweet.
But Johnson later hit back, accusing the Labour leader of “playing Russia’s game”.
The deletion, immediately seized on by the Russian embassy, has deepened the government’s difficulties after British scientists at the UK’s defence research laboratory announced on Tuesday that they had not established that the nerve agent used to poison Sergei and Yulia Skripal had been made in Russia.
After Porton Down said it had “not identified the precise source” of the poison, the Foreign Office issued a swift rebuttal saying the prime minister had always been clear that the assessment was “only one part” of the intelligence picture.
The announcement prompted claims from the Kremlin that Britain was lying about the origins of the novichok and demanded an apology from Theresa May.
However, it emerged on Wednesday that the Foreign Office had earlier deleted a tweet claiming the British scientists had concluded that the nerve agent was “produced in Russia”.
In an awkward development for the Foreign Office, the Russian embassy’s Twitter feed pointed out that the 20 March tweet on a presentation by Britain’s ambassador to Moscow on the Salisbury attack had disappeared.
The deleted tweet read: “Analysis by world-leading experts at the Defence Science and Technology laboratory at Porton Down made clear that this was a military grade nerve agent produced in Russia.”
Johnson is now under growing pressure to explain whether the government has shifted its position.