A small energy company, Union Jack Oil, said there may be as much as 5.4 billion barrels of oil and 2.7 trillion cubic feet of gas in British shale deposits.

Union Jack holds a 10 percent stake in a license area in the central United Kingdom dubbed PEDL201. The company said in a statement Monday an independent site assessment indicates the potential in shale oil and gas in the area is enormous.

The company said that, even if recovery rates are on the low end of what's possible, the volume of oil and gas taken from the region could have a "significant commercial value."

Union Jack cautioned there's no certainly that any portion of the oil and gas thought to exist in the license area will be cost-effective to produce.

The company says it plans to drill two conventional exploration wells into the reserve area by July.

The British government says shale resources could ensure energy security for a country where imports will account for more than half of the country's demands in the coming decades.

Shale exploration is in its infancy in the country. Cuadrilla Resources, a British shale pioneer, has been the target of frequent protests from activists concerned about the environmental impacts of shale development.