Dubai is backing a Kremlin-linked energy company in an offer to buy the last and biggest of Russia's wholesale power-generating companies in a potential $5bn-plus deal that could mark the first strategic foray into Russia by a Middle Eastern fund. Anatoly Chubais, Russia's former privatisation chief and chief executive of Unified Energy Systems, said on Monday that Roskommunenergo, a Russian energy company, had joined Dubai World the investment arm of the United Arab Emirates to offer to buy OGK-1.