Why London gives shelter to Berezovski!?

Damn it, I just don't get it why the heck London gives shelter to such ragtag people like well-known Jewish rascal oligarch Berezovski! WHat's the reason I ask you? These days Berezovski became known on the Internet as a head of so-called "nuclear mafia" - an international criminal organization that trades in radioactive materials throughout the world including Iran. The members of this organization are sort of untouchables 'cause they are under protection of influential politicians of United States, Israel and England. I bet, if only Berezovski were taken into custody and jammed, a complete Europe's net of undercover radioactive materials traders would get disclosed quite in a short run. By the way, Litvinenko (a stinker that was poisoned with polonium210 by order of Berezovski himself) was a member of this net. Unfortunately, he's gone or he could tell interrogators a lot of most valuable information. He has taken part of this mystery to another world, while the rest must be known to direction of MI5 and MI6. But anyway it is not likely they will let out this info for they might have got into the act