The story advances a recurring pro-Kremlin disinformation narrative casting the Skripal poisoning, and by consequence the Navalny poisoning, as entirely unconnected to Russia.
Moscow's involvement in the poisoning has been proven via a thorough investigation. The British Police have presented a solid chain of evidence on the Skripal case, with pictures, connecting the suspects to the locations in the case. Parts of the material have been released to the public. The evidence was sufficient to charge two Russian nationals, Anatoliy Chepiga and Aleksandr Mishkin with the attack on the Skripals, both Russian military intelligence operatives from the GRU, who travelled to the UK using fake names and documents. The picture of the bottle that contained the poison was published by Scotland Yard after a Salisbury couple Charlie Rowley and Dawn Sturgess were intoxicated by the same substance. Ms. Sturgess died from the poison.
Following this attack, the United Kingdom notified the OPCW, invited them to confirm the identity of the substance involved, and briefed members of the Security Council. The OPCW’s independent expert laboratories confirmed the UK’s identification of the Russian produced Novichok nerve agent, specifically the purity of the toxin while emphasising that the OPCW team “worked independently and was not involved in the national investigation by the UK authorities. No State Party was involved in the technical work carried out by the Technical Secretariat, to ensure the integrity of the examinations and investigations.
According to the UK intelligence assessment, based on open-source analysis and intelligence information, in the past decade, Russia has produced and stockpiled small quantities of Novichok agents, long after it signed the Chemical Weapons Convention.
Novichok was developed in Russia in the 1970s and 1980s. It is so unusual, that very few scientists outside of Russia have any real experience in dealing with it and no country outside of Russia is known to have developed the substance. Reports about the substance can be read here and here.
See more disinformation cases on the Salisbury poisoning.