He seems to raise some interesting questions, some of which have been troubling this writer for a while.
Firstly; if this nerve agent is quite so powerful how come it took three hours (from contact on the door knob) to Sergey Skripal and his daughter collapsing on a park-bench in Salisbury? It seems a bit unlikely. Perhaps it was just a tiny amount or a ‘weak’ batch (perhaps because of insufficient or dated precursors being used to prepare the substance?) – but then, if so, this is looking more like an amateur hit than an assassination by the Russian state.
To this Murray adds the interesting observation that Mr Skripal and his daughter apparently fell ill at exactly the same time – on the park bench. All the press reports describe them being found unconscious together. If one had fallen unconscious before the other they would surely have got help? But the length of time a poison takes to take effect is usually dependent on body-mass (plus perhaps other factors to do with the circulation). Murray suggests this casts doubt on the door knob theory which seems to imply that they both touched the door at more or less the same time. (Of course one can posit that they acquired different levels of the toxin from the door and this then balanced itself out in terms of body-weight – but this seems to be stretching probability a bit).
Mr Murray does not mention it in his article but in the very early reports on this case there was mention of an opioid, fentanyl, being found in the vicinity. Fentanyl is sometimes found in street heroin or even sold as a street drug directly. It is a powerful synthetic opioid. It is easy to manufacture – within the reach of criminals.  (It could also be a tool of choice in an assassination of course).
Mr Murray does at least imply that the Met police anti-terror squad may be planting evidence about the door knob and alleged “Russian trainng manuals”.
Given the inconsistencies in the UK government story, their inability to decide if it is a case of “case proven” or “very likely”, the fact that the alleged chemical nerve agent used is far more widely available and readily produced than the public was at first led to believe, the rather too convenient story about a Russian training manual and door-knobs, the welcome but striking apparently full recovery of the Skripals from a nerve agent whose last victim, a Soviet scientist who was accidentally exposed, died after a long and protracted series of illnesses,  plus of course, the sheer unlikelihood of the Russian state doing something like this at this moment, it really doesn’t seem completely far-fetched to speculate that the whole operation was a stunt by British intelligence. It doesn’t fit with this writer’s pre-conceptions of what British intelligence would and wouldn’t do. But.
The Porton Down chief executive Gary Aitkenhead (apparently a former Motorola executive according to Mr Murray – which shows the links between the Western corporate world and the military) said that they could not be sure of the “precise origin” of the substance. This is interesting. There are two ways such substances can be attributed; i) what is the chemical composition and who has the capacity to synthesise these chemicals and ii) they can contain impurities which can be used to link them to specific production centres – if samples exist. There are two ways then of interpreting “not possible to ascertain precise origin”. One is – this is standard corporate world/pseudo-science gloss for “not possible at all to have any idea of origin”. The other, more interesting one, would be to ask Mr Aitkenhead what other countries are indicated by the sample analysis? Uzbekistan? Kazakhstan? Ukraine? The UK?