The case has been going through the courts for four years and related to a dispute over the cap on claims for tax relief on leases of plant and machinery under Part 8ZA of the Corporation Tax Act 2010.

The Norwegian oil drilling company successfully defended the claim twice, once at the First Tier Tribunal in 2020 and then at the Upper Tribunal in 2022.

The UK Court of Appeal has now ruled for HMRC, forcing Dolphin Drilling to be liable to pay £9.9m in tax and £2.9m in interest.

Aberdeen based Dolphin Drilling leased a drilling rig from an affiliated company in Singapore named Borgsten Dolphin.