The Nerve Agent Too Deadly to Use. Until Someone Did
nytimes.com
nytimes.com
> For nearly three decades, since a Soviet whistle-blower told the world of its existence, the nerve agent Novichok has scared American weapons experts.
Cursory research would reveal that Novichok is a family of nerve agents, connected by the fact that they were likely to be unknown to NATO.
More generally, it seems a strange claim for the UK government to make that the nerve agent was definitely a Novichok. This admits a level of knowledge of the substances that leads to serious questions, that nobody is asking, about whether this knowledge comes from having synthesised it. In order to study the effects and the time it takes for effectiveness, both details which the UK appears to have, synthesis would be very useful.
If this is the case then Russia is not the only party capable of synthesis and this partly explains what the mysterious Porton Down facility has been working on since the Chemical Weapons Convention came into force in 97.
On the other hand, it is highly likely that different production processes and even batches have unique chemical signatures that allow origin of a specific sample to be determined with a reasonable probability. This is the sort of information that US weapons experts would have collected during the USSR collapse...again simply because they were professionals.
To me the most likely case is that the story is partially horseshit and that the identification of the origin is reasonably derived from evidence (there's also other intelligence that could indicate the origin).