A controversial new technique for drilling gas wells, which campaigners say has polluted water courses in America, is to be tried for the first time in Britain later this month.
Supporters of hydraulic fracturing or "fracking" say it could unleash so much gas across the globe that it will solve the energy crisis for the next century, as well as help reduce carbon emissions.
But an Oscar-shortlisted documentary film, released in Britain later this month, claims the use of the process in America has resulted in gas contaminating water supplies. Such is the concern that New York has introduced a moratorium on exploration of gas in the state while safety concerns are looked into.
Substantial deposits of shale gas have been found near Blackpool in Lancashire and later this month the exploration company Cuadrilla Resources will carry out a test using the controversial "fracking" technique, which is designed to unlock gas molecules trapped in hard rock, rather than those which have gathered into easily exploitable pockets or reservoirs.
Horizontal wells are drilled thousands of feet underground along shale deposits into which a chemical cocktail is then poured. When compressed, it creates hundreds of fissures in the rock, freeing the gas molecules and allowing them to rush into the well and to the surface.
In America, there are now 35,000 such wells, and the process is already meeting 10 per cent of the country's gas demands. This success has led to a "gas rush", with companies exploring across Europe, India and China for shale gas deposits. There are thought to be huge amounts in Holland and Poland.
Cuadrilla Resources, based in Lichfield, Staffs has been exploring the Bowland shales near Blackpool for the last year. Last month, Cuadrilla's major shareholder, the Australian mining company AJ Lucas, described its Blackpool test well as the "first 'true' shale gas well ever drilled in Europe", adding that the finds "confirm and possibly exceed expectations".
Cuadrilla believes shale gas could potentially meet up to 10 per cent of the UK's energy needs. Its test in Blackpool will decide if the well is commercially viable by the end of the year.
But campaigners warn that not enough is known about the potential adverse effects of the process.
The Co-op, which is distributing the documentary, called Gasland, has commissioned its own report which will be released later this month. Parliament's Energy and Climate Change Committee has also launched an inquiry into the exploitation of shale gas in the UK.
However, Blackpool Green Party is demanding an immediate moratorium on drilling and further work at the Blackpool site. "We are concerned that there has been little interest at any level of government in public safety and the impact on the Lancashire countryside," said Philip Mitchell, party chairman.
He has written to the Department for Energy and Climate Change asking that further licences should not be granted. "This is the first time that Cuadrilla has carried out drilling activities and [its] record is untested."
Greenpeace and Friends of the Earth have also expressed reservations about the gas, although they also say it could prove to be important in bridging the gap between coal and the development of renewable energy resources.
John Lamb, spokesman for Lancashire Friends of the Earth, said the concerns were from the chemicals used in the process as well as gas polluting the groundwater.
"Finding gas in the Bowland shales could be a disaster for the environment," he said. "There's also an unknown risk to wildlife. If it is viable to produce the gas then we will certainly be mobilising against it."
Friends of the Earth's national climate change spokesman, Mike Childs, added: "Excavation of shale gas has the potential to create underground water pollution. It's something they are trying to get to grips with in the States. It's unknown because it really is a new technology. We need to see much more research on the impact on groundwater and a clear strategy from government."
Greenpeace is also concerned. "Shale gas is transforming the world market for gas, but there are a lot of unanswered questions, particularly in the way that fracking is overseen," Charlie Kronick, Greenpeace's senior climate campaigner, said. "There have been huge problems in America with the impact on groundwater."
Supporters argue, however, that the concerns have been exaggerated and are counterbalanced by the enormous potential of shale gas to provide energy security and reduce carbon emissions.
Nick Grealy, a gas advocate who publishes the No Hot Air website, said that the problems with shale gas had been "over emphasised". "It's two or three incidents from thousands of wells. There is so much shale gas that the energy crisis is solved."
Cuadrilla co-founder Chris Cornelius said: "There are certain cases in the US where certain operators have been documented as having some issues and they do exist but I think we have done everything here, working with the Health and Safety Executive and the Environmental Protection Agency to ensure that it doesn't happen on Cuadrilla's location."
Gaslands is released on 21 January.
t An influential committee of MPs will on Thursday demand tighter safety restrictions on oil companies drilling in British waters, amid concerns over the implications of the BP spill in the Gulf of Mexico.
Members of the Energy and Climate Change Committee decided to call for greater scrutiny of oil and gas operations after they were unconvinced by the industry's assurances that they could drill safely in key areas including the North Sea and the rougher waters west of the Shetland Islands.
"The companies have a lot of knowledge about safety precautions, but they weren't always sure that their proposals would work. These things are far too important to be left to trial and error," one MP said.