A cramped courtroom in ­central London was the unlikely setting for the battle of the Russian oligarchs on Friday, as Boris Berezovsky and Roman Abramovich kicked off a £2bn ($3.9bn, €2.5bn) dispute over their share in some of Russia’s largest companies.

Mr Berezovsky, a vocal critic of the Kremlin who lives in exile in London, is suing Mr Abramovich for allegedly threatening and intimidating him into selling his stakes in Sibneft, the Russian oil group, and Rusal, the aluminium maker, for far less than they were worth.