Personally, I don't think Lugovoi could be more obviously guilty even if he had "GUILTY" written across his forehead in flashing neon letters, but at most he's only guilty of being a delivery boy, and as for who he was working for - god knows.

The British government's response to the incident and its actions since have been petulant, ridiculous and hysterical though. The visa regime for Russians visiting the UK is exactly the same as for nationals of many other countries, so when some minor government hack tries to link the continuation of tough rules to the Litvinenko case it's just pure bluster. The rules are as they are because the British establishment currently finds it expedient to dissuade all but the richest foreigners from coming here, and for no other reason. It doesn't even have anything to do with Russia, specifically, let alone one little detail of the UK's relationship with Russia.