Following the decision last year by New York state to ban fracking for natural gas, a group of senior doctors and academics in the UK has called for a similar, nationwide moratorium on the extraction technique. This would extend the ban on "unconventional oil and gas extraction" announced by the Scottish government earlier this year to the rest of the UK. The Welsh Assembly has already passed a motion against fracking, which is a highly controversial technology in many European countries and not widely deployed there.

In a letter published by the British Medical Journal, the health professionals write: "Fracking is an inherently risky activity that produces hazardous levels of air and water pollution that can have adverse impacts on health. The heavy traffic, noise and odour that accompanies fracking, as well as the socially disruptive effects of temporary ‘boomtowns’ and the spoilage of the natural environment are additional health hazards."

They point out that the UK is likely to suffer the ill-effects of fracking more than other countries because of its greater population density. This would lead to gas extraction taking place close to communities, rather than in more isolated locations. The letter notes that there are also strong environmental reasons to ban fracking, because contrary to some claims, shale gas extraction would "be incompatible with global efforts to prevent global warming from exceeding two degrees centigrade."

The letter concludes: "The arguments against fracking on public health and ecological grounds are overwhelming. There are clear grounds for adopting the precautionary principle and prohibiting fracking." The precautionary principle is not only a touchstone of much European policy, but enshrined in the EU's defining treaty.

The letter is prompted by a new report, "Health & Fracking: the impacts & opportunity costs," produced by Medact, which describes itself as "a charity for health professionals and others working to improve health worldwide." It says it is independent and that in 2013 over 95 percent of its income came from donations by supporters.

The letter and report put the group and charity at odds with current UK policy. In 2014, British Prime Minister David Cameron declared that his government was "going all out for shale," and in 2015 he rejected calls for a ban. Uncertainties over the composition of the next UK government after the General Election being held in May this year make it very hard to predict what the UK's future policy on fracking will be. If a ban is not introduced in the UK, previous protests are likely to continue.