 ENERGY COMPaNIES are planning a huge increase in the number of British drilling sites for shale gas, as arguments rage over whether the controversial fuel is safe.  Under a new government "licensing round" early next year - the first since 2008 - bids for shale gas exploration licences are expected to surge, industry experts have told The Sunday Telegraph.  The company responsible for Britain's only active shale gas drilling, Cuadrilla Resources, recently claimed a gigantic 200 trillion cubic-foot find at its site near Blackpool, Lancashire, the biggest discovery in Europe if con-firmed.  Supporters say shale gas could be a "game changer" for Britain, restoring its selfsufficiency in energy, raising billions in taxes and cutting CO2 emissions by displacing higher-emitting fossil fuels such as coal. They claim Britain could follow the United States, where volume shale gas production has reduced energy prices.  Opponents say shale gas will stop Britain meeting its climate targets and condemn the controversial technique used to obtain the fuel, called "fracking," which involves fracturing the shale rock with a high-pressure mixture of water, sand and chemicals. The "Frack Off" campaign group describes fracking as a "nightmare" causing "toxic and radioactive water pollution, tap water you can set on fire, earthquakes and runaway climate change".  Both sides agree that shale gas could prevent the installation of more than 4,000 large wind turbines - last week branded "useless" by the Duke of Edinburgh - but disagree on whether this is a good thing.  In a document seen by The Sunday Telegraph, the Department for Energy and Climate Change has identified large areas of eastern and southern England as having the "best shale gas potential". The main area identified runs from just south of Middlesbrough in a crescent through East Yorkshire, Lincolnshire, Northamptonshire, Buckinghamshire and the Cotswolds to Somerset and Wiltshire.  It then turns along the South Coast and Downs, including most of Dorset, Hampshire, Sussex, Surrey and Kent. Shale gas sites are under investigation in the Sussex commuter belt, near Haywards Heath, the Mendip Hills, south of Bath, in Kent, Lincolnshire, south Wales, Staffordshire and Cheshire, as well as more sites near the existing find in Lancashire.  One firm, Celtique Energie, estimates that there may be as much as 14 trillion cubic feet of recoverable shale gas in countryside south of Horsham, West Sussex, for which it already has a licence.  Bill Transier, the chief executive of Endeavour Energy UK, whose US arm controls 68,000 acres of shale in Pennsylvania, said his company would be "very active" in the licensing round.  Several of the potential sites will be controversial. The leader of Bath council has expressed concern that planned test drilling in the Mendips could taint the city's famous spa waters. In Lancashire, Cuadrilla has said that about 800 wells on 80 separate sites might be needed to extract its find, with a commensurate impact on the landscape.  The developments come as many arguments in the shale gas debate are exposed as misrepresentations. Frack Off, the British campaign group, says fracking is a "new method" that is being "pioneered" and "trialled" by Cuadrilla. It says that the shale gas exploration in Lancashire is "Britain's first fracking project".  In fact, fracking is not new and has been used without previous controversy since the 1940s. a spokesman for Cuadrilla said that an existing gas well at Elswick, near one of its sites in Lancashire, was fracked 20 years ago by its then owners, British Gas, in "almost exactly the same way" as at Cuadrilla's shale sites now.  The Elswick site has been producing conventional gas without controversy since 1996. The spokesman accused Frack Off of using "misleading information" to scare people.  Frack Off insisted that shale gas fracking was new and different because it would have to be done more often and at greater pressures.  among the most effective tools used by anti-shale campaigners is an Oscar-nominated film, Gasland, showing three residents of Weld County, Colorado, with water so contaminated that they could set fire to it as it came out of their kitchen taps. The dramatic scenes, blamed by the film on fracking, were described by Chris Huhne, the Energy Secretary, this year as "extremely alarming" and "a bit of a wake-up call".  However, the state government of Colorado said the film's director, Josh Fox, ignored or dismissed investigations by scientists that found that the contamination in two of the cases was caused by naturally-occurring methane gas and had nothing to do with fracking or the gas industry.  Mr Fox said that in the third case of flaming tap water, the state had found the contamination was partly related to the industry. In the other two cases, he said that natural gas could have migrated as a result of fracking. The process "is inherently contaminating, and no amount of regulation can make it safe", he told an american newspaper.  Cuadrilla insists that there is no prospect of water contamination because the fracking takes place far below the water table and the drilling shaft that passes through the water levels is thickly sealed with concrete. Jonathan Craig, the chairman of the Geological Society's petroleum group, told MPs on the energy select committee that "having bad cement jobs on your wells" can result in contamination, "but that is exactly the same in conventional [oil and gas] exploration ... The fracks themselves are not the cause of contamination."  Even many in the green movement do not support all the claims made against shale gas. Prof Kevin anderson, a shale gas expert at the Tyndall Centre for Climate Change Research, said: "The jury is out on there being a direct and causal link on environmental effects. With bad practice, there is a risk, but with proper regulation the environmental impacts could be brought to the levels we deem acceptable for natural gas."  Prof anderson warned, however, that current regulation of the industry was "inadequate" and depended too much on taking operators' statements on trust. Cuadrilla admits that its operations in Lancashire "triggered" two small earthquakes, one of 2.3 magnitude and the other of 1.5. Fracking has been suspended ever since. 