"The potential is catastrophic," he said. "We don't know the science of this or how it will affect people. We are introducing something that we do not know the full dangers of."
Greens claim that there is the risk of explosive well blow-outs, fire, traffic disruption and noise. They fear that, so significant are the deposits and so huge the rewards, the industry could be on the verge of major expansion not just across Lancashire but the whole of the UK.
To add to the sense of unease this week, France's National Assembly voted to ban the process after a sustained protest by green groups. The Senate is expected to follow suit next month making France the first country to ban fracking. (French environmentalists are furious though that a last-minute deal means that research employing the technique will continue.)
Cuadrilla Resources, currently the only holder of a UK fracking licence, believes the process is entirely safe. At present operations are regulated by the Department of Energy and Climate Change (DECC) as well as the Environment Agency. The official line is that no one knows how much gas is there until the exploratory phase is completed nor how much it will cost to recover.
In the meantime the company has been conducting a charm offensive inviting local people, journalists and MPs to tour the site. This week the chief executive Mark Miller, from Pennsylvania, compared modern drilling technology to keyhole surgery. He said a dozen wells could be drilled on an area the size of a football pitch with each site capable of feeding gas into a generator capable of producing 100 megawatts of local electricity for the next 30 years.