M UCH OF THE time and money spent trying to ignite a shale-gas boom in Britain over the past decade or so has gone not on drilling boreholes for hydraulic fracturing (“fracking”) but on lobbying for permission. Fracking’s backers have had politicians to woo, regulators to persuade and a wary public to reassure. It seemed to be working. In October, after years of vigorous promotion, a firm called Cuadrilla started fracking at two wells on a site near Blackpool.

But frackers appear to have been outclassed on the public-relations front. On April 26th the government’s shale-gas tsar, Natascha Engel, said she was resigning, after just six months in the job. The government pays more attention to anti-fracking campaigning by environmental groups such as Greenpeace than to businesses ready to invest, she complained.

The antis cite earthquakes, water pollution and global warming as reasons to fight fracking (shale gas emits far less than coal but is a fossil fuel). Well-organised protesters have dug in at Cuadrilla’s Preston New Road site. The final straw for Ms Engel appears to have been the attention lavished on Greta Thunberg, a teenage Swedish protester against climate change who told Parliament last month that British support for shale gas was “beyond absurd”.

Fracking experts retort that the real absurdity is the regulatory straitjacket that Britain has imposed in response to public fears incited by NGO s. Upon Cuadrilla’s first frack, at another site near Blackpool in 2011, earth tremors of magnitude 2.3 and 1.5 were set off and operations had to stop. The firm’s main backer, AJ Lucas, an Australian mining-services firm, had been too gung-ho, says an industry insider (both firms deny this). In 2014 David Cameron, then prime minister, promised to go “all out” for shale, to replicate America’s booming industry and improve energy security. But rules later obliged firms to suspend fracking whenever tremors reached magnitude 0.5. In many places, including America, magnitude of up to 4 is allowed.

Cuadrilla is now finding it cannot frack effectively within the limit. Once its injection of high-pressured water has created the right fracture network through which gas can escape upwards, says Quentin Fisher, a fracking expert at Leeds University, the resulting tremors hit the threshold before engineers can get enough sand in to keep the flow-paths open. So far Cuadrilla has made no return from shale gas, after investing around £200m ($260m).

Nor has the firm been the best standard-bearer for fracking. The tremors in 2011 handed ammunition to Greenpeace and other opponents. As for its objection to the 0.5-magnitude limit, defenders of the rule note that the company accepted the framework and made no complaint until this year, when it ran into difficulties.

Without an upward revision of the seismicity ceiling, says Ms Engel, time is running out for fracking in Britain. She wants the government to ask regulators to review the 0.5-magnitude limit, or to indicate that it will do so, by the end of the year.