Russian oil giant Yukos has failed to bring a halt to state-owned rival Rosneft's stock market flotation.
Yukos was hoping that the British high court would give it permission to apply for a judicial review of the decision by the London Stock Exchange and the Financial Services Authority (FSA) to allow the listing to go ahead.
But yesterday the court ruled in Rosneft's favour meaning that, unless there is an appeal, the way is clear for one of this year's most controversial IPOs.
Yukos lost one of its main oil fields to Rosneft when it was forced to auction off its assets by the Russian government following a probe into alleged tax evasion.
The investigation, which is widely-regarded as having been politically motivated, also landed Yukos boss Mikhail Khodorkovsky in jail.
The Rosneft flotation has attracted attention from a number of oil firms and is expected to raise over £5.5 billion.
BP will buy a £1 billion stake, which is seen by analysts as an attempt to protect its exiting and future interests in the region.
Russia is becoming an increasingly important energy provider for western countries amid sustained geopolitical disruption in key oil-producing regions.
President Vladimir Putin has offered assurances that Russia can be a reliable partner, but has shown that he is prepared to use oil and gas to further his political objectives.