An oil exploration firm has uncovered what it describes as the largest undeveloped discovery on the UK Continental Shelf.

Hurricane Energy said one billion barrels of oil could be contained within the Halifax well in the Greater Lancaster Area (GLA), 60 miles west of Shetland.

The company found oil in two wells about 19 miles apart and says the combined discoveries have proved the presence of a giant field.

It hopes to begin production in 2019.

Dr Robert Trice, Hurricane's chief executive, said: "This is a highly significant moment for Hurricane and I am delighted that the Halifax well results support the company's view that its substantial Lancaster discovery has been extended to include the Halifax licence.

"We believe that the GLA is a single hydrocarbon accumulation, making it the largest undeveloped discovery on the UK Continental Shelf.

"The discovery of a 1km (0.62-mile) column at Halifax validates the efforts the company undertook to acquire the licence and drill, test and log the Halifax well through the winter months.

"Given the positive well results, the Halifax well has been suspended to provide the company the option to return to undertake further testing as well as provide the option to deepen the well and thereby establish a definitive oil water contact.

"These are exciting times for Hurricane."

Shares rose 6% in early trading after the announcement.

Hurricane Energy has made no further developments there for budget, time and safety reasons but has the option to return.

The 2016/17 drilling campaign is now complete, with Hurricane having a 100% success rate with the drill bit.

Meanwhile, international energy services company Wood Group has been awarded a £40 million contract with Premier Oil to deliver topside operations and maintenance services to the Balmoral floating production vessel (FPV) in the central North Sea and the Solan installation, west of Shetland.

The two-year contract retains more than 150 jobs and extends Wood Group's support of Premier Oil in the UK Continental Shelf.

Dave Stewart, chief executive of Wood Group's Asset Life Cycle Solutions business in the eastern region, said: "This contract clearly demonstrates the strong partnership we have developed with Premier Oil in the North Sea, renewing our support of the Balmoral FPV and broadening our delivery to include the Solan field, which came on stream in April 2016.

"We have consistently and successfully assured the management of safety and integrity and applied our innovation and technical expertise to maximise uptime and production, whilst also reducing field lift costs.

"This will be our continued focus - leveraging both our late life asset management expertise and production enhancing technical solutions as we continue to collaborate with Premier Oil on the safe and effective delivery of this latest contract."

Paul Wheelhouse, the Scottish Government minister for business, innovation and energy, said: "Today's announcements of the first oil from the Flyndre field and the undeveloped discovery within the up to one billion barrels of oil equivalent thought to be recoverable from the Greater Lancaster field make it clear that the continental shelf in waters adjacent to Scotland, such as areas to the west of Shetland, continue to hold very significant potential.

"In total, it is estimated that up to 20 billion barrels of oil equivalent remains under the North Sea and in the wider basin.

"Our draft Energy Strategy outlines that the Scottish Government remains committed to maintaining domestic oil and gas exploration and production, and maximising economic recovery.

"The UK Government currently holds the key fiscal levers. While the outcome in the Flyndre and wider Greater Lancaster fields has been very welcome, it remains clear that without the right support for greater investment and activity, we risk losing vital capacity and skills which will support ongoing production and ensure we maximise economic recovery from the North Sea and best sustain domestic energy security."