A company backed by former BP chief Lord Browne claims to have found a gas field near Blackpool that could be the largest ever discovered in Britain.
Cuadrilla Resources believes there are 200 trillion cubic feet of "shale" gas in the Bowland basin, which could result in a Lancashire gas boom creating 5,600 jobs at peak production.
Shale is a type of onshore gas common in the US, which is extracted by blasting apart rock in a process called fracking.
More testing is needed, but the estimates suggest Britain could have more shale gas than Poland, which has been considered Europe (Chicago Options: ^REURTRUSD - news) 's biggest holder of probable reserves.
Cuadrilla hopes to start work on more test wells this autumn. However, it is currently banned from drilling over fears this caused a tremor in Blackpool earlier this year. It is waiting for the Government to decide whether it can restart.
Its (Paris: FR0010370163 - news) 200 trillion figure has not been independently verified and often only a small percentage of a probable reserve can be extracted. Current estimates for UK shale gas potential are just 4.2 trillion cubic feet.
Executive director Dennis Carlton said initial results show a basin five to 10 times thicker than America's Marcellus shale.
Discoveries of shale have tranformed the US gas industry though, at some sites, there have been claims that fracking contaminates drinking water.