Vladimir Chizhov told the BBC that Russia did not stock the toxin, and said that the Porton Down lab was only eight miles (12km) from Salisbury — where the attack occurred.
In response to a question on how the nerve agent ended up in Salisbury, he told the BBC: "Porton Down, as we now all know, is the largest military facility in the United Kingdom that has been dealing with chemical weapons research."
On Saturday, Russia ordered 23 British diplomats to leave Moscow within a week, in retaliation for Britain's decision to kick out 23 Russians, amid an escalating row between both countries over a nerve agent used — since World War Two — in the attempted murder of former Russian double agent Sergei Skripal and his daughter.
Chizhov told BBC that in addition, there were "certain specialists", including scientists, claiming they have created some nerve agents, who are now living in Britain.
Mr Chizhov said that Skripal could "rightly be referred to as a traitor" but "from the legal point of view the Russian state had nothing against him", according to the BBC report.
UK's foreign office said there was "not an ounce of truth" in what he is saying about Porton Down, and dismissed it as "nonsense," the report said.