Well. I'm a British 'outsider' living in the US too. And and I see it like Classycara. To think other than these poisonings being the responsibility of Russia (Putin, in particular) is cloud cuckoo.
But you have absolutely no evidence to back up your conclusions, only a 'most likely explanation'. Occam's razor has been waved all around. Yet I offer a much simpler explanation, and its considered 'cuckoo' on here? How many times have you heard of syringes washed up on shorelines? Foeteses showing up in waste tips? It is not unusual to have medical & other hazardous 'waste' incorrectly disposed of. As Tom Jones sings, its not unusual. I realize that explanation doesn't fit your preconceived notions, but try and step back.
I think the world outside the UK accepted the UK version of events when the story first broke, but have become less convinced as they find more holes in that narrative than in Blackburn, Lancashire.
Carra, I didn't mean to ignore you. I think the onus is on the UK Government to back up its assertions with hard evidence, not for me or anyone also to prove a negative. The evidence is just not forthcoming. Instead, accusations being cast and diplomatic co-operation being avoided. The case would being presented would never stand legal scrutiny.
I'm also left wondering why the official response to this latest episode is more muted vis-a-vis Russian accusations.