It is "extremely unlikely" that ground water supplies would be polluted by methane as a result of controversial "fracking" for shale gas, UK geologists have said. Professor Mike Stephenson, of the British Geological Survey, said most geologists thought it was a "pretty safe activity" and the risks associated with it were low. There was no evidence in peer-reviewed literature of pollution of water by methane as a result of fracking, he said, adding that the presence of the gas in US water supplies was likely to be natural. --The Press Association, 10 January 2012