A spot in the south of England near Gatwick airport could hold a massive amount of oil even larger than that found at the North Sea oil fields.
Investigations at the site in Horse Hill by UK Oil and Gas Investments (UKOG), have discovered the site could hold up to 100bn barrels of the black stuff - dwarfing the 45bn barrels produced by the North Sea in the last 40 years.
2017 update: shares in UKOG have just jumped 60 per cent
However, the difficulty of extracting the oil may mean this could be limited to as little as three per cent of the total available and up to 15 per cent.
UKOG chief Stephen Sanderson said the discovery had "world class" potential for "significant daily oil production" and was the biggest onshore oil discovery in the last 30 years.
"Drilling the deepest well in the basin in 30 years, together with the ability to use concepts, techniques and technology unavailable in the 1980s, has provided new cutting-edge data and interpretations to comprehensively change the understanding of the area's potential oil resources," said Sanderson.
Shares in the Aim-listed oil and gas company exploded in early trading following news of the discovery.
The Horse Hill site is located in the Weald Basin, an area spanning Sussex, Surrey, Kent, and Hampshire, which already produces oil leading some to refer to it as Britain's Dallas.
The discovery of 100bn barrels far surpasses the original estimates of the volume of oil in the area, which had been put at 4.4bn barrels by previous geological surveys.
The Weald Basin contains five types of shale, all of which have the potential as oil resources, similar to that found in North America. It also has potential to produce hybrid oil - a combination of conventional and shale oil.