Chorley and South Ribble are sitting on huge reserves of underground gas – according to an expert report released last week.

The announcement greatly increases the prospect of widespread fracking – drilling down into the earth before before a high pressure water mixture is directed at the rock to release the gas inside – close to the boroughs.

The British Geological Survey’s (BGS) study of shale gas resources in Lancashire doubled estimates of reserves and extended the potential drilling area from the Fylde right across the county.

Experts on both sides of the bitter argument over whether fracking, or hydraulic fracturing, of shale rock to produce natural gas was safe, said Chorley and South Ribble were now prime candidates for the process. As the battle lines for a bitter dispute were being drawn with opponents claiming the technique causes mini-earthquakes, water contamination and infla- mmable gas to come through taps.

Lawrence Carter of Greenpeace said the area was now ‘in line for potential fracking’ and Manchester University geology professor Ernie Rutter said it was a ‘prime target’ for the technique which he supports.

Friends of the Earth’s Brian Jackson said: “I am horrified. The economic benefits are questionable and the potential environmental effect disastrous.”

But Prof Rutter has welcomed the news. He said: “This has huge potential for boosting the economic revival of the area. It is safe. Once people starting seeing the pounds in their pockets, they will be less worried about environmental concerns.”

The next set of oil and gas exploration licences will be issued early next year and a Department of Energy spokesman confirmed that parcels of land in Lancashire would be among those on offer.

The BGS report estimates there may be 1,300 trillion cubic feet of shale gas present across Lancashire and Yorkshire ‘Bowland Basin’, double previous estimates, and highlighted key areas where it was available close to the surface and in larger quantities further underground and both.

Chorley and South Ribble are seen as key targets for firms seeking exploration licences.

Michael Fallon, Energy Minister, described shale gas as ‘an exciting new energy resource’ and announced measures to encourage shale gas drilling as part of its infrastructure plans.

Once experimental drilling has established gas is economically recoverable, commercial drilling could take place within five years producing hundreds if not thousands of wells linked to extensive pipelines.

Drill heads are able to exploit resources over a wide area underground once established through high-pressure water jets.

There is also controversy over how much of the gas can be economically extracted with experts estimating only 10% is recoverable.

This could be 130 trillion cubic feet, far in excess of the three trillion cubic feet of gas consumed in the UK each year.

BGS technical director Prof Mike Stephenson said: “Shale gas clearly has potential in Britain but it will require geological and engineering expertise, investment and protection of the environment.”

Mr Carter said: “This could mean between 50,000 and 100,000 fracking wells, a steady stream of trucks passing through communities, environmental risks such as water contamination and as yet unknown impacts on property prices.”

Mr Fallon unveiled a package to encourage fracking development including streamlined planning guidelines, tax incentives to encourage exploration,up to £100,000 in ‘community benefits’ and one per cent of revenues from productive wells for local neighbourhoods.

Lancashire County Council leader Jennifer Mein, said: “This report will add to the already considerable level of commercial interest in exploiting Lancashire's shale gas reserves.”