Multiple statements. Two quick examples: Boris Johnson saying only Russia could do this and May stating that the only options are Russia did it or Russia lost control of their nerve agents. Both Johnson and May stating as fact that only Russia could produce this.
OK so what is the problem there?
No. The fact that other countries have produced Novichok nerve agents shows that it can be done. There's nothing uniquely impossible about one specific nerve agent. Your argument is akin to saying just because Germany produced a Mercedes (one type of car) doesn't mean that they could produce a different sort of car. Yes - it's all very similar technological capability. Oh, and to clear up your imprecision, Iran produced five example types for the OPCW, btw. The capability for other countries to produce these agents is demonstrated - this is a fact.
that is fine but you're missing the point - is the specific nerve agent found one of the specific ones that other countries could produce? You don't know... you just know it is of a type and that Iran has supposedly produced some of that type and then you've (incorrectly) concluded that the UK has lied.
CT? Conspiracy Theory? If you think this is conspiracy theory then you have lack understanding of international politics. Maybe read the FT or the Economist sometime. That you refer to this actual and real thing that is being done right now and talked about widely as "conspiracy theory" indicates you don't pay attention. What it has to do with this is that it creates a real economic threat to US financial hegemony. If oil is no longer sold in dollars, that undermines the dollar significantly because the dollar is essentially backed by three things: oil, the ability to pay US debt in it and US military might. And the last one is used primarily to ensure the first, currently.
Again what does this have to do with the Russian being poisoned... yup we're into tin foil hat territory.
Please do link to any FT or Economist article that links the "petroyuan" to this case... you can't.. it is conspiracy nonsense.