Horse Hill

PEDL 137
Operator: Horse Hill Developments Ltd; UK Oil and Gas plc (UKOG) has a controlling 85% interest

Planning consent granted in September 2019, for four more oil production wells, a water reinjection well and oil production for 20 years. This has been subject to a long-running legal challenge which was heard in the Supreme Court on 21–22 June 2023. 

Read more about the legal challenge


Horse Hill is in Green Belt countryside west of Horley and north of Gatwick Airport. Two exploratory oil wells, called HH-1 and HH2, were drilled in 2014 and 2018 respectively, and flow testing has taken place

In September 2019, Surrey County Council granted Horse Hill Development Ltd (HHDL) planning permission for four more oil wells, plus one wastewater reinjection well, and 20 years of full oil production. This was granted in September 2019. Read a summary of UKOG’s plans on the Drill or Drop website.


Demo at County Hall 11 Sept 2019Demonstration at County Hall as the application for massive expansion at Horse Hill is decided, 11 September 2019

Legal challenge

Sarah Finch, a Redhill resident,  applied for a Judicial Review of Surrey County Council’s decision to allow this massive expansion. Her claim was dismissed in the High Court. However an Appeal Judge, Lord Justice Lewison said that the EIA argument “has far reaching ramifications” and “the emission of GHG is a matter of considerable public concern”. He added that “although the judge’s reasons for his conclusion are cogent, they are open to proper challenge; and in view of the importance of the question, I regard this as a compelling reason for the appeal to be heard”. The Appeal was heard in November 2021 and the Court of Appeal dismissed the Appeal with a a split two-to-one ruling.

In the run up to the COP26 Climate Summit in November 2021, Friends of the Earth says that it is one of four cases that threaten the UK’s climate reputation – along with the Whitehaven coal mine, the Cambo oil field, and export credit for LNG in Mozambique


  • Horse Hill Air Quality protest

Protest about air pollution from the Horse Hill drill site, February 2019


The plans to drill at Horse Hill have met with opposition at every stage.
The Norwood Hill Residents’ Association, which represents households living immediately around the drill site, has opposed the planning applications and engaged with the oil companies and the Environment Agency over their concerns.

Other local residents, and people involved in the campaigns against drilling at other nearby sites including Balcombe, Brockham and Leith Hill, have organised public meetings and leafleting drives to inform residents about the plans, and held demonstrations at the site.

For many years a protection camp monitored activity at the site and raised awareness of the activities there.

Protest at Horse Hill 2016
Protest during flow testing in 2016


The Horse Hill site is located near the epicentre of the swarm of earthquakes that started in April 2018, and are unprecedented in Surrey.

There is controversy about whether the earthquakes are caused by the drilling. A workshop convened by the Oil and Gas Authority in October 2018 to investigate the cause of the earthquakes concluded there was no causal link between oil drilling and seismic events. However, this was not a unanimous conclusion – and it was only reached as the workshop disregarded the existence of the Horse Hill well site altogether, as they believed there was no activity there at the time of the first quake. This was later established to be false.

An independent assessment by geologists at Edinburgh University reached the opposite conclusion. Their report, ‘Further Potential for Earthquakes from Oil Exploration in the Weald’, published in February 2019, said: “Our assessment supports the concern that Horse Hill oil exploration triggered the earthquakes. We infer that future oil exploration and production close to critically stressed faults in the Weald is likely to result in similar earthquake events.”

Esso drilled just to the north of the current site in the 1980s. They are now believed to have drilled on the wrong side of a fault, and oil companies remained interested in potential oil finds at this site.

In 2012, Magellan was granted planning permission for the construction of an exploratory wellsite including one well (named HH-1). However they did not proceed and instead formed a partnership with Horse Hill Developments Ltd.

The well HH-1 was drilled in October 2014 and flow tested in 2016. UKOG claimed to have flowed more than 1500 barrels per day from the Upper and Lower Kimmeridge limestone layers and the Portland sandstone. (The Kimmeridge shale formations are an unconventional target, which require techniques such as acidisation to exploit them.)

In November 2017, HHDL received planning permission to drill a sidetrack (horizontal) well and a second vertical well (HH-2) and for flow testing.

Read more

Local campaign groups