Russia’s EU ambassador has suggested a UK research laboratory could be the source of the nerve agent used in the attack on an ex-spy and his daughter.
Vladimir Chizhov told the BBC’s Andrew Marr Show Russia had “nothing to do” with the poisoning in Salisbury of Sergei Skripal and his daughter Yulia.
He said Russia did not stockpile the poison and that the Porton Down lab was only eight miles (12km) from the city.
The government dismissed his comments as “nonsense.”
Retired military intelligence officer Mr Skripal, 66, and Yulia, 33, remain critically ill in hospital after being found slumped on a bench in Salisbury city centre on 4 March.
UK Prime Minister Theresa May has told MPs that Porton Down – Britain’s military research base – identified the substance used on them as being part of a group of military-grade nerve agents known as Novichok developed by the Soviet Union.
The Russian government has denied any involvement in the attack.
Foreign Secretary Boris Johnson said experts from the Organisation for the Prohibition of Chemical Weapons will come to the UK on Monday to test samples of the nerve agent.
Mr Johnson, speaking to the BBC’s Andrew Marr Show, described Mr Chizhov’s claims as “satirical”, adding that it “is not the response of a country that really believes itself to be innocent”.
He said the UK had evidence that Russia, within the last 10 years, had been developing and stockpiling Novichok, as well as investigating the delivery of nerve agents for the purposes of assassination.
Labour shadow attorney general Shami Chakrabarti reiterated Labour’s position that the incident was either a “loss of control” by the Russian state or a “malevolent directed attack”.
She told the BBC: “You’re not going to get co-operation from a state that’s deliberately targeted you but you might get co-operation even from a slightly embarrassed state if its lost control of its stock of chemical weapons.”
Mr Chizhov told the BBC that Mr Skripal could “rightly be referred to as a traitor” but “from the legal point of view the Russian state had nothing against him”.
Asked how the nerve agent came to be used in Salisbury, he said: “When you have a nerve agent or whatever, you check it against certain samples that you retain in your laboratories.
“And Porton Down, as we now all know, is the largest military facility in the United Kingdom that has been dealing with chemical weapons research.
“And it’s actually only eight miles from Salisbury.”
But pressed on whether he was suggesting Porton Down was “responsible” for the nerve agent in the attack, Mr Chizhov said: “I don’t know. I don’t have any evidence of anything having been used.”
He said a number of scientists who claim to be responsible for creating some nerve agents “have been whisked out of Russia and are currently residing in the United Kingdom” but no stockpiles of chemical weapons had left the country after the collapse of the Soviet Union.
He added that there were “no stockpiles whatsoever” of nerve agents left in Russia.
Russia, he said, stopped producing chemical weapons in 1992 and destroyed all of its stockpiles last year.
The Foreign Office said there was “not an ounce of truth” in Mr Chizhov’s suggestion of a link to Porton Down.
A spokesperson said: “It’s just another futile attempt from the Russian state to divert the story away from the facts – that Russia has acted in flagrant breach of its international obligations.”
Mr Chizhov’s comments come after a Russian foreign ministry spokeswoman said the UK was one of the most likely sources of the nerve agent, along with the Czech Republic, Slovakia, Sweden or possibly the United States.
Maria Zakharova said a large number of ex-Soviet scientists had gone to live in the West, “taking with them the technologies that they were working on”.
Czech foreign minister Martin Stropnicky said the claims were “unsubstantiated” and “a classic way of manipulating information in the public space”, while Sweden also “forcefully” rejected the suggestion.
Chemist Vil Mirzayanov, who revealed the existence of Novichok in the 1990s and later defected to the United States, said he was convinced Russia created the substance used in the attack.
He told the BBC: “Russia is the country that invented it, has the experience, turned it into a weapon. This is the country that has fully mastered the cycle.”
On Saturday, the Russian foreign ministry said UK staff would be expelled from Moscow within a week, in response to Britain’s decision to expel 23 Russian diplomats.
It also said it would close the British Council in Russia, which promotes cultural ties between the nations, and the British Consulate in St Petersburg.
The UK foreign secretary will meet his EU counterparts and Nato Secretary General Jens Stoltenberg for talks in Brussels on Monday.
Mr Stoltenberg said he expects Germany’s Angela Merkel and other leaders to reassess their response to Russia at the next Nato summit in July.
He told German newspaper Welt am Sonntag: “Salisbury follows, by all appearances, a pattern we’ve observed for some years – Russia is becoming more unpredictable and more aggressive.”
Theresa May said the UK government would consider its next steps “in the coming days, alongside our allies and partners”.
She said: “Russia’s response doesn’t change the facts of the matter – the attempted assassination of two people on British soil for which there is no alternative conclusion other than that the Russian state was culpable.”
Addressing the Commons last week, Mrs May said the decision to point the finger at Moscow was also based on “Russia’s record of conducting state-sponsored assassinations and our assessment that Russia views some defectors as legitimate targets for assassinations”.
On Saturday, counter-terrorism police renewed their appeal for sightings of Mr Skripal’s burgundy BMW 320D saloon car, registration HD09 WAO, in Salisbury on the morning of Sunday, March 4.