RUSSIAN billionaire Boris Berezovsky has never made any secret of his loathing for President Vladimir Putin, but in an interview in his London exile the controversial tycoon went one step further with a vow to mount a coup. "President Putin violates the constitution and any violent action on the opposition's part is justified today, and that includes taking power by force, which is exactly what I am working at," the oligarch, looking vibrant despite five years in self-imposed exile, said at his Piccadilly office. For the past 18 months, "we have been preparing to take power by force in Russia",...