But it is not known how much of this oil could be commercially extracted – and any extraction would have to use the controversial fracking process.
The study has been published as the government announced a consultation to make land more readily available to fracking companies, in order to speed up its introduction.
The survey, conducted by BGS and the Department for Energy and Climate Change (DECC), looked at southern England and found that a large area of Jurassic rock beneath the Weald Basin was likely to contain oil.
The Weald Basin crosses swathes Hampshire, Sussex, Surrey and Kent, from Winchester in the west to Rye in the east.
According to the survey, the area sits on anything between 2.2 and 8.6 billion barrels (293-1.143 million tonnes) of oil and a negligible amount of gas. By way of comparison, the North Sea has produced in the region of 45 billion barrels of oil over the last 40 years.
What is fracking?
Fracking is the process of extract oil or gas from Jurassic shale rocks by pumping water, sand or chemicals into rock at high pressure to fracture ("frack") them and force out the oil or gas trapped within.
The process has proven controversial, attracting concerns that it will pollute natural water supplies and cause earthquakes.
“It is not known what percentage of the oil present in the shale could be commercially extracted,” the BGS said. “In order to estimate the shale oil reserve, drilling and testing of new wells will be required to give a better idea of oil production rates.
“In addition, non-geological factors such as oil price, operating costs and the scale of development agreed by the local planning system will affect the amount of oil produced.”Fracking has been identified by government as a means to achieve energy security in Britain. It is controversial, however - despite a series of reports suggesting that fracking, conducted with care, is not harmful, it continues to attract opposition. These include a series of anti-fracking protests in Sussex last summer.
Nevertheless, government is hoping to accelerate the process of introducing the extraction technique. A new consultation proposes fresh rules that would allow shale oil and gas companies readier access to land 300m below the surface.
Announcing the proposal, energy minister Michael Fallon said: “Britain needs more homegrown energy. Shale development will bring jobs and business opportunities.”
Nick Clack, senior energy campaigner for the Campaign to Protect Rural England
, said:“If the government is going to win support for fracking it must demonstrate that it’s serious about protecting the landscape, climate, and local communities. This latest government-commissioned study suggests there may be billions of barrels of shale oil under southern England, but we need many more guarantees about how our communities and countryside will be safeguarded.
"The government has the opportunity to go about this properly and make its case. But unless it can demonstrate that it gives a high priority to protecting our landscapes and wider environment, and is willing to engage openly with those who are alarmed by the potential impact of fracking, this potential shouldn’t be tapped."
Image courtesy of British Geological Survey