“There are 4,000 SSSIs in England, more than 1,000 in Wales and 1,425 in Scotland.”

“Fracking will still be excluded from national parks, areas of outstanding natural beauty, the Broads and world heritage sites, under the new plans, though shale companies will be allowed to put a rig outside a national park and drill horizontally underneath it.

Some of the SSSIs will fall within the borders of those other protected areas, but even so the RSPB believes thousands of SSSIs could potentially be affected.

Matt Williams, a policy officer at the RSPB, said: “The government has reneged on its commitment to rule out fracking in some of our most important wildlife sites.

“Despite promising in January to exclude fracking from SSSIs, today’s announcement ignores any such commitment, leaving some the UK’s most valuable wildlife sites exposed to risk from future fracking.”

SSSIs are described by government officials as the “best of our wildlife, geological and physiographical heritage”.

Daisy Sands, head of energy at Greenpeace UK, said: “With a few days before recess, this looks like nothing but a blatant attempt to bypass democracy to sneak this deeply unpopular policy in through the back door while no one is looking. Ministers have given concerned citizens up and down the country no opportunity to voice their opposition to the plans that could ruin the countryside, contaminate the water supply and have a devastating impact on the climate.”

The draft regulations, which will be debated in September, also said that fracking would be allowed under protected groundwater source areas, where drinking water is gathered.

Even under the most sensitive of those groundwater areas (SPZ1s), fracking will be allowed so long as it at depths of more than 1,200 metres. A limit deeper than that would “hinder the exploitation of potentially valuable shale gas reserves”, the regulations said.

No public consultation was held on either the dropping of SSSIs from the list of protected areas from where fracking would be excluded, or how deep the groundwater limits should be set.”