London has directly accused the Kremlin on at least three occasions of being behind the chemical attack on former double agent Sergei Skripal and his daughter, Yulia.  

This is a direct quote from the British ambassador to Russia, Laurie Bristow. The tweet has since been deleted by @foreignoffice. This does not look good for the UK government. pic.twitter.com/Bvp7Ir2uXA

— Liam O'Hare (@Liam_O_Hare) April 4, 2018

Bizarrely, the Foreign Office denies Foreign Secretary Boris Johnson claimed the novichock “categorically” came from Russia, despite a recorded interview clearly showing he did.

WATCH: Boris Johnson blatantly lies to Deutsche Welle and says Porton Down lab were “absolutely categorical” that Russia was behind the Salisbury nerve agent attack

On 03/04/18, Porton Down lab said they are unable to confirm the origin of the nerve agentpic.twitter.com/Uhxes9ptVn

— Socialist Voice 🌹 (@SocialistVoice) April 3, 2018

The Foreign and Commonwealth Office (FCO) itself stated: “Analysis by world-leading experts at the Defence Science and Technology Laboratory at Porton Down made clear that this was a military-grade Novichok nerve agent produced in Russia.”

However, the tweet was deleted and an FCO statement said: “An HMA Moscow briefing on 22 March was tweeted in real time ... One of the tweets was truncated & did not accurately report our Ambassador’s words. We have removed this tweet.”

The Foreign Office has not yet deleted a tweet in which the UK's ambassador to Russia, Laurie Bristow, reiterates the accusation of Moscow being behind the poisoning. 

However, the UK government openly denied wrongdoing or confusion. A Foreign Office spokesman told Huffington Post there is no discrepancy between the Porton Down statements and their own.

He said: “The Foreign Secretary was making clear that Porton Down were sure it was a Novichok – a point they have reinforced. 

“What the Foreign Secretary said then, and what Porton Down have said recently, is fully consistent with what we have said throughout. It is Russia that is putting forward multiple versions of events and obfuscating the truth.”

British Ambassador to Russia Dr Laurie Bristow has briefed the international diplomatic community in Moscow on the UK Government response to the Salisbury attack https://t.co/TOknU0j8gb pic.twitter.com/jrB2r9MuEg

— Foreign Office 🇬🇧 (@foreignoffice) March 22, 2018

Jeremy Corbyn has said Johnson had “egg on his face” because his claims were not backed up by evidence.

He told Sky News: "Boris Johnson has serious questions to answer. He claimed on German television that this was a Russian-produced nerve agent and Porton Down then examined it and said all they could identify it was as novichok. They couldn’t say where it came from, and the chemical weapons organisation is meeting to continue that discussion about where it goes from here. The Foreign Office then issued a tweet in support of what the foreign secretary said, and then removed that yesterday after Porton Down had said they couldn’t identify the source of it.”

The UK Government has repeatedly blamed Russia and said the Organisation for the Prohibition of Chemical Weapons (OPCW) will back them. However, Moscow denies all culpability. Vladimir Putin’s spokesman, Dmitry Peskov, said Britain would have to apologize to Russia for its “mad accusations”.

Britain has also convinced 28 other states to expel Russian diplomats with its claims. Johnson could also be in hot water after he denied making claims Russia was behind the attack.

The row between Russia and Britain is reaching boiling point as officials from the OPCW meet Russian representatives on Wednesday.