You might have noticed a recent news item reporting claims that a monumental gas field has been found in the North West.

Cuadrilla Resources, which has been carrying out test drilling, claims that it has found 200 trillion cubic feet of gas under Lancashire, in an area roughly bounded by Blackpool and Southport on the coast and Chorley further inland.

200 trillion cubic feet, according to some estimates, would power the UK for 50 years. The British Geological Survey claims that this estimate is nuts and that 5 trillion cubic feet could be nearer the mark.

Squeezing the gas out of the shale rock in which it is trapped is a very tricky business. Roughly, you have to drill a bore hole and then force sand, water and chemicals down it at huge pressure. This mix then pushes the layers of shale apart and lets the gas out.

The process, called ‘fracking’, is already the subject of huge controversy in the US. It might cause tiny, localised earthquakes. If the shale beds are close to the surface, and locals use bore holes for water supply, some claim you can find methane mixed into the water supply.