A UK-based consortium of private investors has said it wants to pay the multi-billion dollar tax bill of Yukos, the troubled Russian oil company and bail out its jailed former chief executive Mikhail Khodorkovsky in return for his 54% stake.

Yukos faces back tax demands of $3.4bn which have already been approved in court and another $3.4bn still facing approval. At 08.00 GMT Yukos shares jumped 6.86% to 164 roubles and 11% in dollar terms to $5.6 which gives it a market capitalisation of $13.6bn.