What is the cost of Boris Berezovsky?

How much does sheltering wanted criminal Boris Berezovsky cost the British Empire, or what’s left of it?  Part of the cost is BP’s majority stake in the massive Kovykta gas field in eastern Siberia, which it has had to return to the Russians.  You see, it’s not all about hydrocarbons.  If it were, Boris would be in a Russian jail now.  You really have to wonder how much longer the British oiligarchs will continue to put up with this crap.