Energy giant BP has been granted approval for a North Sea development which it is hoped will produce 20 million barrels of oil.
The Alligin field is part of the Greater Schiehallion area off the west of Shetland.
Approval has been granted by the Oil and Gas Authority (OGA). It is expected to come on stream in 2020.
BP said Alligin would see "stranded reserves" being accessed using existing infrastructure.
The energy firm had announced the development of Alligin, as well as Vorlich field in the central North Sea, in April.
BP North Sea regional president Ariel Flores said: "Six months later we have achieved regulatory approval. Always maintaining our focus on safety, we are modernising and transforming how we work in the North Sea to fully realise the potential of our portfolio."
Mike Tholen, upstream policy director for Oil and Gas UK, said nine new field developments had been approved in 2018 - the same number as in the previous three years combined.
Zennor Petroleum has also received field development plan approval for its plans in the Finlaggan field in the central North Sea.
"As the year draws to a close we are seeing an improved landscape for the sector after one of the most testing and prolonged downturns in its history," said Mr Tholen.
"It's why industry, governments and the regulator must remain focused on strengthening the competitive investment conditions which are breathing fresh life into the basin and providing new business for the supply chain."
However, Friends of the Earth Scotland director Dr Richard Dixon said it was a "reckless decision" which was "incompatible with efforts to tackle climate change.
"This oil needs to stay under the seabed."
Gina Hanrahan, head of policy at WWF Scotland, said it was "galling" to see North Sea oil production increase.
"We need to see a just transition that enables us to harness the engineering skills currently deployed in the North Sea and apply them to supporting a range of cleaner forms of energy production," she added.