Friends of the Earth (FoE) has been criticised for misleading the public about the health and environmental impacts of fracking by the advertising watchdog.
The green group published leaflets falsely claiming that fracking could cause cancer, contaminate water supplies, increase asthma rates and send house prices plummeting, according to a draft ruling by the Advertising Standards Authority.
The finding, which was leaked to The Times newspaper, was in response to a complaint by energy firm Cuadrilla. It was produced in July but has been repeatedly delayed due to requests for more time by FoE.
The draft says: "This ad must not appear again in its current form. We told Friends of the Earth Trust Ltd not to make claims about the likely effects of fracking on the health of local populations, drinking water, or property prices in the absence of adequate evidence."
FoE pointed out that the decision is a draft which it is in the process of challenging "with further evidence".
ASA confirmed there is an ongoing investigation into a leaflet by FoE and it will publish its findings in due course.
Separately, Labour announced today that it would ban the controversial drilling technique to focus on the development of low carbon energy.
“Fracking locks us into an energy infrastructure that is based on fossil fuels long after our country needs to have moved to renewables,” shadow energy secretary Barry Gardiner said.
"The next Labour government will back the clean technologies of the future."