A senior security official told Newsnight there were “very strong indications it was a state action”. ==
I agree completely. There has been some recent articles by investigative journalist which claims there was no assassination at all. A simple case of polonium smuggling and accidental contamination. This makes the most sense to me since polonium is too expensive and too dangerous to the potential assassin to ever be considered a realistic choice for the purpose of assassination. If smuggling is involved it does bring up a rather more frightful scenario which explains why the Brits would rather take the murder angle.