The official story would always be vague. This is spook territory not regular police. A Scotland Yard team went to interview Litvinenko's assassins (One of whom was being treated for radiation poisoning - fancy that!), and they were completely outgunned by the FSB.
Also, as to CCTV, it is extremely prevalent in London but not as omniscient in places like Salisbury.
Security services sit on information like this for years, possibly never to reach daylight i.e. it's at best 50/50 whether MI5's director(Hollis) in the 50s and 60s was a double agent for the GRU, but we will never know what is in the archives. It is undeniable, however, that the Russian's did it - a Russian nerve agent just happens to turn up in the middle of Salisbury!?
Also, as to CCTV, it is extremely prevalent in London but not as omniscient in places like Salisbury.
Security services sit on information like this for years, possibly never to reach daylight i.e. it's at best 50/50 whether MI5's director(Hollis) in the 50s and 60s was a double agent for the GRU, but we will never know what is in the archives. It is undeniable, however, that the Russian's did it - a Russian nerve agent just happens to turn up in the middle of Salisbury!?