More than 71,000 hectares of protected countryside in the south-east face risk of drilling

More than 71,000 hectares (177,000 acres) of protected countryside, including national park land, in the south-east of England are at risk from a new wave of oil drilling, environmental campaigners have warned.

Under threat are areas of outstanding natural beauty in the Weald, which runs between the north and south downs, and the South Downs national park, Greenpeace said.

A mapping analysis by the group found that around 71,000 hectares of protected areas overlap with oil and gas exploration licenses awarded by the government for the south-east, across an area stretching from the Surrey Hills in the east to the Isle of Wight to the west.

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The warning comes as campaigners in Surrey prepare to deliver a petition with more than 100,000 signatures against plans for an oil well at Holmwood, south of Dorking.

While high profile efforts to frack in the north of England and the Midlands have been stalled and delayed, several companies are preparing to drill conventional onshore wells later this year in the south of the country.

The big prize is the oil within and around the Kimmeridge formation, which has been likened by the industry to major fields in the US.

The plans do not involve fracking, but in some cases will use a technique known as acidisation, where diluted hydrochloric acid is put down a well to dissolve limestone, releasing the oil trapped within, as well as oil within adjacent shale formations.

Hannah Martin, Greenpeace UK head of energy, said: “Energy firms have got their eyes on the shale oil buried under some of the best-loved nature sites in the south-east. Fracking operations are banned within these sensitive areas, but the industry is now planning to get the oil out by pumping acid into the ground.”

One of the most promising oil wells is the Horse Hill site near Crawley, dubbed the Gatwick Gusher after encouraging initial tests by UK Oil & Gas Investments PLC (UKOG).

The company is undertaking a 150-day testing programme ahead of commencing drilling of a well at the site towards the end of summer. UKOG hopes to be commercially producing oil by spring next year.

UKOG’s licences for the Horse Hill work included protected areas known as sites of special scientific interest, but the company said it had no plans to drill in protected areas and was fully aware of their sensitivity.

“Rather than importing essential resources from potentially untrustworthy foreign sources, we believe that this country’s energy security is an issue of paramount importance and that indigenous oil has a key role to play in this regard,” the company said.

Other prospects include a site near the village of Balcombe in West Sussex, which is licensed to fracking firm Cuadrilla but will be operated by another company, Angus Energy. Cuadrilla recently won a planning green light to test for oil flows at an existing well there.

Facebook Twitter Pinterest Leith Hill, near Holmwood in Surrey. Activists are protesting against plans by Europa Oil and Gas to drill and test for oil in Bury Hill Wood. Photograph: Mark Kerrison/Alamy

To the west of Horse Hill is Holmwood, which Europa Oil and Gas plans to drill during the second half of this year. The site is in an area of outstanding natural beauty, which the company said planners had concluded would not be impacted by oil drilling.

Hugh Mackay, the company’s chief executive, said the well was similar to a dozen other discoveries made in the Weald over the last three decades. “There’s no new technology here, it’s a typical Weald basin oil prospect.”

The company has planning permission, and the Environment Agency has said it is minded to approve the project. On Thursday night at 7pm, campaigners against the drilling will hand in a petition signed by 102,000 people to the government body, urging the EA to block the drilling.

The petition’s organiser, who did not want to be named, told the Guardian: “We are deeply concerned for the pollution risks this drilling proposal presents to our water supply.”