Prospectors have made the biggest oil discovery in the UK in 30 years - and say the true amount sitting underneath the south of England could be an unprecedented tens of billions of barrels.
The substance has been found near Gatwick - but some analysts are sceptical about how much of it can be extracted.
ITV News Science Correspondent Alok Jha reports:
To gleefully rub your hands at a new fossil fuel discovery you need to turn the clock back to the 19th century and ignore everything we have learnt about climate change since.
We already have more than enough coal, oil and gas reserves to fry the planet. Dotting the English countryside with drilling rigs and pipelines to squeeze the last drop of oil out of Britain doesn't make any sense.
It's time we uncoupled our economy from the dangerous rollercoaster of fossil fuels and invested in the clean technologies that can provide safe and cheap energy for decades to come.
David Lenigas, Chairman of UK Oil & Gas Investments, has spoken to ITV News about the firm’s discovery of oil reserves near Gatwick Airport.
He told Business Editor Joel Hills: "It’s a very significant discovery, 158 million barrels a square mile. The Weald Basin itself is 1,100 square miles, we’ve got 55 square miles and its pervasive.
“It’s like a big sponge, 1,500 ft thick with vast amounts of oil in it with three big limestones that you can effectively suck the oil out of the sponge. It’s a great find. There’s a lot more work to be done to bring it into proper production but eventually this will be a very key part of Britain’s strategic energy resource.
When asked about the vast difference in the oil potential projections of UKOG and the British Geological Survey for the area - who estimated between shale oil resources of 2.2-8.5 billion barrels - Mr Lenigas said people should believe the "last well that was drilled..(which was his company's) because drill holes don't lie."
UK Oil & Gas Investments has published a report providing further details of its discovery of reserves which could contain as much as 158 million barrels of oil.
The "significant" discovery at a well in Horse Hill in the Weald Basin near Gatwick Airport is subject to ongoing analysis to determine the "regional potential of the Weald Basin".
Britain could see a significant increase in oil production after a geologists discovered reserves which could be as much as 100 billion barrels near Gatwick Airport.
The discovery at the Weald Basin by exploration firm UK Oil & Gas Investments (UKOG) is a "possible world class potential resource," the company said.
Geologists found 158 million barrels per square mile and it is estimated up to 15% could be recovered.
In 15 years the site could provide up to 30% of the UK's oil demand.
The company considers that the high pay thickness, combined with interpreted naturally fractured limestone reservoir with measurable matrix permeability, gives strong encouragement that these reservoirs can be successfully produced using conventional horizontal drilling and completion techniques.
Appraisal drilling and well testing will be required to prove its commerciality, but this Weald hybrid play has the potential for significant daily oil production.
Oil giant Royal Dutch Shell is to buy exploration firm BG Group in a deal valuing the British business at about £47 billion.
The companies unveiled details of the huge merger, the biggest in the industry for several years, in a statement to the London stock exchange.
The swoop by the Anglo-Dutch company comes as the oil industry looks to become more efficient and reduce costs in the face of falling energy prices. BG Group, which employs about 5,200 staff in 24 countries, was created in 1997 when British Gas demerged into two separately-listed companies.
The UK oil and gas industry says it has suffered its worst losses in decades and is facing a bleak future.
Falling oil prices and rising costs meant the sector spent billions more than it earned in sales last year and now it is calling on the government to help.
ITV News Reporter Sejal Karia has more:
A new report has found "striking evidence" of how rising costs, taxes and "inadequate regulation" have taken their toll on energy companies.Read the full story ›
Two British oil companies have posted huge drops in profit for 2014 compared with the year before.
BP reported a 20% drop in underlying profit for the fourth quarter of 2014, dropping to $2,239 million, compared with $2,809 million for the same period in 2013.
BP said the fall in profits was due to tumbling value of oil, with chief executive Bob Dudley saying: "We have now entered a new and challenging phase of low oil prices through the near and medium term."
Britain's third-biggest energy company BG Group full-year total operating profit fell 14% year on year to $6.5 billion, while earnings slipped 8% to $4 billion.
Ed Miliband says Britons has attacked the Conservatives for "denial, complacency and failure" on the British public's standard of living.
After David Cameron suggested companies benefiting from falling oil prices should pass the savings on to staff in pay rises, the Labour leader said the Prime Minister's words would have people "choking on their cornflakes".
"This is someone who has spent months and years telling us there was no cost of living crisis, and then if there ever was one, it had been fixed," he said.
He criticised Cameron for "running from" the planned TV debates, and claimed that "for the first time since the 1920s, working people will be worse off at the end of a government than they were at the start."