BP, the UK energy company with a large stake in Rosneft, could become the biggest owner of the state-owned Russian energy conglomerate's shares after it joined the race to acquire a 9.4% stake held by bankrupt oil company Yukos.

TNK-BP, BP's Russian joint venture, will go head to head with Rosneft itself for the stake, worth at least $7.5bn (€5.6bn), after the Russian company confirmed earlier this week that it had secured a multi-billion dollar loan from a consortium of international banks to allow it to take part in the auction.