To those that delude themselves by imagining that an operation like this is part of some fairy tale, my conclusion is they must be living in the same fairy tale. And WTF the Falklands war has got to do with the current situation I do not know, what next, parallels with Mata Hari?
If countries like North Korea can assassinate senior members of its country's elite on foreign soil with the limited resources it can muster, what is stopping a country like Russia with the resources it possesses carrying out this sort of operation. The Russian state, driven by Putin, is out to re-establish its position on the centre of the world stage, having lost considerable ground after the fall of communism. Boasts about advanced nuclear weapons, restablishing their position in the Middle East by aligning with Syria's Assad, annexing Crimea, cheating at world sports events to appear to be world beaters be are all part of this posturing, not least to keep the man at the top in a job. They are constantly pushing the boundaries, examples of this being the occasional high profle harrassment of our borders by the Russian military. As I said above 'they seem to be able to carry out these sort of covert operations with impunity and there's not a lot we can do to stop them'. Expulsions, economic sanctions will be met by the same measures. So they really have nothing much to lose by carrying out an operation like this. It demonstrates that they have the power to do it if they choose to do so, without serious repurcussions to them, and it certainly won't precipitate any retaliatory action that undermines their position on the world stage. And lets be honest who's going to stop them?