LONDON — An oil exploration firm says it has made the "largest undeveloped discovery" of oil in UK waters.

Hurricane Energy said in a statement on Monday morning that it had identified a huge oil field on a site in the North Sea, 60 miles west of Scotland's Shetland Islands.

The BBC reported that the site — called the Greater Lancaster Area (GLA) — could hold up to one billion barrels of recoverable oil, although that is only a fifth of the size of the Forties field, the largest existing site in the North Sea.

The company's tests indicate that two sites where it has drilled — which are around 30 miles apart — are part of the same huge oil field, described as "a single large hydrocarbon accumulation."

Dr Robert Trice, Hurricane's chief executive officer, said it was a "highly significant moment for Hurricane."

"We believe that the GLA is a single hydrocarbon accumulation, making it the largest undeveloped discovery on the UK continental shelf," he said.

The discovery of an oil-bearing column at least 1,156 metres deep was described as "very significant" in the statement.

The company said that testing operations ceased for financial and safety reasons, but added that it plans to return for further testing.

Shares in Hurricane Energy had risen nearly 9% by late afternoon trading. Here is the chart as of 3.50 pm B.S.T. (10.50 am ET):