The firm plans to release a statement later today giving details of the London court’s ruling.
Rival firm Excalibur launched legal action against Gulf Keystone in 2010, arguing that it is entitled to a 30 per cent interest in some of the latter’s assets in northern Iraq.
A positive verdict to the court case would be a much-needed boost for Gulf Keystone, which announced in June that annual pre-tax losses had widened to £80.2m.
Gulf Keystone has been feted as a potential takeover target for energy explorers looking to tap into its assets in northern Iraq.
“The market may perceive the conclusion of the case as a removal of an obstacle towards the sale of the company and thus, the resolution may have a positive impact on the day,” said Dragan Trajkov, analyst at Westhouse. Shares closed 2.3 per cent higher at 187.75p.