By Susanna Twidale
LONDON (Reuters) - Britain should begin exploratory drilling or fracking of shale gas sites to allow the industry and government to fully assess its economic benefits for the country, a shale gas industry-funded task force said on Tuesday.
Britain is estimated to have substantial amounts of shale gas trapped in underground rocks and Prime Minister David Cameron has promised to go "all out for shale", hoping it will help reduce dependence on energy imports, generate additional tax revenue and create thousands of jobs.
But exactly what kind of benefit it can bring cannot be established until developers are allowed to start exploratory drilling, the report by the task force on shale gas said.
"We know roughly where there are shale rocks and where there is likely to be shale gas but exactly how much is genuinely recoverable no one knows at the moment," Chris Smith, chairman of the task force, said.
Analysis published in 2013 by the Institute of Directors estimated shale gas production could generate 74,000 jobs and attract investment of 3.7 billion pounds ($5.6 billion) a year at its peak.
Hydraulic fracturing, known as fracking, which injects water, sand and chemicals into rocks to release hydrocarbons, is used to release the shale gas from rock formations.
Fracking applications have struggled to get approval from local communities, concerned about noise and environmental impacts and the effect on house prices. To address this the government has changed planning rules to make its own decisions on shale gas appeals.
The report, the fourth in a series published by the group, said if best practice methods are used fracking would provide no greater risk to the public's health than other comparable industries such as traditional gas extraction.
It said there could be a negative impact on house prices in regions where a fracking well has been given permission, but added the impact would be negligible a year or more after the well had been drilled.
However, green groups said the government should re-assess its strategy in light of a global climate deal forged in Paris by almost 200 countries.
"If the UK government is really committed to keeping its end of the Paris deal, it must rethink its support for fracking and back safe, cheap, clean energy instead," said Greenpeace UK energy campaigner Hannah Martin.
The task force was set up last year to examine the risks and benefits of shale gas extraction and says it is independent of its funders Cuadrilla, Centrica (L:CNA), Total, Weir Group (L:WEIR), Dow Chemical and GDF Suez (PA:ENGIE) E&P UK.
($1 = 0.6607 pounds)