The precise source of the nerve agent used to poison a Russian ex-spy and his daughter has not been verified, says the head of Porton Down laboratory.
"It's our job to provide the scientific evidence that identifies what the particular nerve agent is ... but it's not our job to say where that was actually manufactured", he told Sky News.
Aitkenhead then hinted towards the involvement of a state actor in the manufacturing of the nerve agent, while pointing out at the sophisticated methods deployed in the manufacturing of the poisonous agent.
The British authorities have blamed Russian Federation for the March 4 poisoning, with Foreign Minister Boris Johnson suggesting it was "overwhelmingly likely" that President Vladimir V. Putin had ordered the attack.
The British government has accused the Kremlin of authorizing a nerve agent attack on Salisbury, South England, against a former Russian military intelligence agent, Sergei Skripal, who doubled as an agent for the British secret services.
Bizarrely, the Foreign Office denies Foreign Secretary Boris Johnson claimed the novichock "categorically" came from Russian Federation, despite a recorded interview clearly showing he did.
"I would like to inform you, although we have already told [you] about that, we are convening a OPCW Executive Council session tomorrow to look into the situation in detail", Putin said during a joint press conference with Turkish President Recep Tayyip Erdogan in Ankara.
Russian Federation has denied responsibility and suggested the poison may have come from Britain.More news: "Affluenza Teen" Ethan Couch Has Been Released From Prison
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Responding to the statement by Porton Down, Russian President Vladimir Putin demanded an inquiry into the Salisbury incident, stating his concern at the "the speed at which the anti-Russian campaign has been launched".
Russia's foreign minister, Sergei Lavrov, suggested the MI6 could be implicated on the assassination attempt in Salisbury to distract public opinion from the Brexit negotiations. They've said that they've identified it was Novichok (nerve agent), they can not identify the source of it. The father-daughter duo has since been hospitalised. Porton Down then said they couldn't and wouldn't identify where it had come from so they then deleted the tweet.
After Mr Aitkenhead's comments to Sky News, the Foreign Office released a statement saying it had been "clear from the very beginning" that Porton Down had identified the type of substance as novichok.
Russia's spy chief has claimed the Salisbury nerve agent attack was "staged" by Britain and the U.S., ahead of an emergency meeting of an worldwide watchdog.
The Organization for the Prohibition of Chemical Weapons (OPCW), the world's chemical watchdog, will meet Wednesday to discuss Britain's allegations that Russian Federation was responsible for the poisoning, according to documents released on Tuesday.
More than 25 countries, including the USA and many European Union member states, collectively expelled over 150 Russian diplomats "in solidarity" with London.
'There is no way anything like that could have come from us or left the four walls of our facility, ' he said.
"We have an interest in a full investigation and want Russian Federation to be allowed to take part in that investigation", he said.