Adura said the public consultation on Rosebank, the UK's largest undeveloped oil field, closed at midnight, a milestone before a government decision on the £8.7 billion project. The consultation, run by the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED), follows a similar process for the Jackdaw gas field that closed last week.

Rosebank and Jackdaw together represent a combined £10.8 billion of anticipated investment, more than three-quarters of it spent in the UK, according to Adura. The two projects are expected to generate £1.4 billion in tax revenue before the end of this parliament, rising to £3.8 billion by the end of the next. Adura said they would support 3,500 jobs at peak construction, 880 ongoing jobs, and 125 apprenticeships.

Rosebank alone is projected to add £24.3 billion in gross value added, a measure of economic output, to the UK economy over its producing life, Adura said. The field, about 130km northwest of Shetland in the UK North Sea, is due to be developed in two phases, with upstream subsea wells tied back to a redeployed Floating Production Storage and Offloading (FPSO) vessel. At peak, Adura said Rosebank could produce around 69,000 barrels of oil a day, about 10% of forecast UK Continental Shelf oil output. Rosebank and Jackdaw combined could supply 10% of UK domestic gas production, the company said.

Neil McCulloch, chief executive of Adura, said Rosebank 'is the largest undeveloped oil field in the UK North Sea.' He said the company would keep working with the regulator as it completes its review of the two projects.

OPRED will now weigh the consultation responses on Rosebank before ministers decide whether to approve the project.