There are huge shale oil reserves under the south of England, the results of a study by the British Geological Survey, or BGS, are expected to reveal.

Vast reserves of the resource are stored across the Weald Basin, just 10 percent of which could fuel the UK's gas supply for 40 years, and among the counties sitting on top of the shale oil are Surrey, Sussex, Kent and Hampshire. But it is not clear exactly how much can be extracted from the ground.

Energy companies looking to exploit the resource are likely to face strong opposition from local planning authorities, residents and environmental campaigners in similar scenes to drilling for shale gas at Balcombe, Sussex, by the firm Cuadrilla.

In a separate 2013 study, the BGS found 1.3tn cubic feet of shale gas reserves lying under Yorkshire and Lancashire.

To encourage exploration and in order to win public support, the government announced a funding package for communities where exploration and extraction takes place. Every affected community will get 100,000 pounds (about $168,000) and 1 percent of revenues from the unconventional gas that is successfully extracted. Firms must also sign up to a community engagement charter to ensure locals are continuously consulted about any work planned.

But there are reports that this will be bolstered to increase the incentive and also offset plans to relax trespass law so energy firms can drill for shale underneath land without needing the owner's permission. And to encourage shale gas exploration, the government has also put in place a number of tax breaks for the industry.

Critics say the hydraulic fracturing -- fracking -- process to extract shale gas is dangerous because there is a risk that the chemicals could leak out and contaminate the water supply. But the government insists that the risk of this is minimal because it operates a strict licensing and regulation regime.

It is keen to encourage shale gas production because it could lead to thousands of new jobs and bundles of tax receipts flowing into the Treasury.