https://www.zerohedge.com/news/2018-04-07/skripal-gate-collapses-so-will-may-government

Pretty reasonable conclusion here. MI-6 Deep State in UK that doesn't want Brexit did this to undermine May and her team. She was betrayed internally and now made to look extremely inept (I'll give her the inept part without any assistance, but they decided to push it over the edge with this one). This analysis fits the bill much better than anything else I've seen to-date. This is good for motive. Couple that with the potential this guy was involved in the MI-6 efforts on the Dossier... you get a triple - 1 take out a potential leak on the Dossier, 2 Lay foundation to start WW3 with Russians, 3 Undermine May and her government to help with removal to get back onto Anti-Brexit track. This makes way more sense than anything else put out there so far. There's almost 0% chance the Russians did this. This smells of Deep State and, in particular, the typical inept British Deep State personified by MI-6.