[sterlind]

You're right - any well-equipped state could have synthesized the nerve agent used on the Skripals. But that's not the only evidence: two suspects were identified, who traveled from Russia and stayed at a local hotel. The nerve agent was found in their hotel room.

Of course, you could argue that British intelligence framed those Russians during the investigation, and poisoned the Skripals themselves as some sort of ruse for expelling diplomats. But if you deny the evidence and proceed down that path, you've made the decision not to alter your beliefs and no discussion will change your mind.