Fracking is a well-stimulation technique in which rock is fractured by a hydraulically pressurized fluid. It requires a borehole to be drilled to target depth in the reservoir. For oil and gas production, hydraulically fractured wells can be horizontal or vertical, while the reservoir can be conventional or unconventional. After the well has been drilled, lined, and geophysically logged, the rock can be hydraulically fractured.
Fracking in the United Kingdom was claimed to have started in the late 1970s with fracturing of some 200 onshore conventional oil and gas wells. The technique attracted attention after licences were awarded for onshore shale gas exploration in 2008. The 200 wells claim had been made by a joint report in 2012 of experts from the Royal Society and Royal Society of Engineering, but turned out to be misleading, in that small-scale local fracking may have been performed at these wells, for example for wellbore cleaning, but no high volume hydraulic fracking (HVHF) had been used, with the exception of the Preese Hall-1 well drilled by Cuadrilla in Lancashire in 2011. The definition of HVHF is discussed below.
The topic received considerable public debate on environmental grounds, with a 2019 high court ruling ultimately banning the process. Only two horizontal wells were ever fracked using HVHF. The operator, Cuadrilla, was supposed to have started plugging and decommissioning these wells in 2022, but in spring 2025 it had not even started.
Definitions of fracking in the UK context
Hydrocarbons are formed in a source rock. They can migrate over geological time to collect in a reservoir rock, from which they may be accessed by conventional drilling and production methods. But the physical properties of a source rock can be altered by so-called unconventional methods, such that the source rock volume becomes the reservoir. Such alteration belongs to the category of well stimulation methods. Well stimulation can apply to geothermal as well as to hydrocarbon resources.
Hydraulic fracturing (fracking) and acidising are two of the most common methods for well stimulation. The flow chart shows that hydraulic fracking and acid fracking are two categories of unconventional hydraulic methods. But acidising is complicated by the fact that matrix acidising is considered conventional. Note that it takes place below the fracture gradient of the rock.
In the UK legislative and hydrocarbon permitting context, Adriana Zalucka et al. (in a peer-reviewed article from 2021) have reviewed the various definitions,Zalucka A, Goodenough A, and Smythe D 2021. Acid stimulation: fracking by stealth continues despite the moratorium in England, Energy Policy 153: 112244. as well as the role of key regulators and authorities, in particular the Oil and Gas Authority (OGA), the Environment Agency (EA), the Health and Safety Executive (HSE) and planning authorities.
They point out that the EA uses terms like 'acid squeeze', which is rarely used by the hydrocarbon industry, and is in any case ambiguous. The definition of HVHF in the Petroleum Act of 1998 is poorly drafted, and uses an excessively large water volume use criterion. 'Associated Hydraulic Fracturing' in the 1998 Act was superseded by 'Relevant Hydraulic Fracturing' in 2016, so that there are now two conflicting legal definitions of what is meant by HVHF. Acid fracking, an important method in the onshore UK context, was not mentioned.
Only three shale wells have been fracked to date in the UK. The authors show that it is possible that none of them would have met the definition of ‘Associated’ hydraulic fracturing, and only Preese Hall-1 (a vertical test well) met the definition of ‘relevant’ hydraulic fracturing. The remaining two wells, Preston New Road-1z and Preston New Road-2, were horizontal wells.
Zalucka et al. conclude that the UK legislation concerning the legal definitions was, and remains, confusing, ambiguous, incomplete, self-contradictory, and full of legal loopholes. To solve this problem they have proposed a new robust definition for unconventional well treatments:
The above definition focuses on increasing permeability, rather than on any particular extraction process. It is quantitative, using the generally agreed 0.1 md cut-off value, below which rocks are considered impermeable. It exempts borehole cleaning processes like acid squeeze or acid wash from being classed as unconventional, by using the 1 m radius criterion. It avoids a definition based on, for example, the quantity of water injected, which is controversial,Smythe, D. and Haszeldine, S. 2017. Could fracking creep under the radar? Nature [Correspondence], 24 August 2017. or the injection pressure applied (whether the treatment is above or below the fracture gradient, as shown in the flow chart above). It also exempts non-hydrocarbon wells from being classed as unconventional.
History
Offshore UK
Experiments on fracking for hydrocarbons began onshore in the US in 1947.
In the UK, the first fracking of an oil well was carried out offshore, shortly after discovery of the West Sole field in the Southern North Sea in 1965. After the industry started to use intermediate and high-strength proppants in the late 1970s, fracking became a common technique in the North Sea oil and gas wells. Fracking from a ship was first conducted in 1980, with HVHF used from 1984 onwards. The target rocks are predominantly tight gas sandstones of Permian and Carboniferous age, and not the thick shales which are the target of most HVHF treatments.
Onshore UK
An estimated 200 conventional onshore wells have been subject to low volume hydraulic fracturing; around 10% of all onshore wells in the United Kingdom, including Wytch Farm, which is the largest onshore conventional oil field in western Europe.
From 1977 until 1994, a hot dry rock geothermal energy experiment was conducted in the Carnmenellis granite of Cornwall. During that experiment, three geothermal wells with depth of were hydraulically fractured "to research the hydraulic stimulation of fracture networks at temperatures below ".
The surge of public interest in high-volume hydraulic fracturing in the UK can be traced to 2008, when Cuadrilla Resources was granted a petroleum exploration and development licence in the 13th onshore licensing round for unconventional shale gas exploration along the coast of Lancashire. The company's first HVHF job was performed on its Preese Hall-1 wellbore in March 2011, near Blackpool, Lancashire. Cuadrilla halted operations due to seismic activity damaging the casing in the production zone. On 2 November 2019, the UK government imposed a moratorium on fracking in England. Scotland and Wales have moratoria in place against hydraulic fracturing.
Only HVHF combined with horizontal drilling was ever considered likely to enable commercial extraction of unconventional hydrocarbon resources, such as shale gas and light tight oil, in the United Kingdom. The areas where hydraulic fracturing was anticipated to be used included the Upper Bowland Shale of the Pennine Basin in Lancashire and Yorkshire, and the Jurassic oil-bearing shales of the Weald Basin in Hampshire, Surrey, Sussex and Kent.
The national parks with geology of possible interest included the North York Moors (shales), the Peak District (shales and coals), the South Downs (shale oil) and to the south of the Yorkshire Dales (shales and coals).
The subsequent report of 2012 by experts from the Royal Society and the Royal Academy of Engineering concluded that earthquake risk was minimal, and recommended the process be given nationwide clearance. However, it highlighted certain concerns which led to changes in regulations.
In January 2014, the European Commission issued a set of recommendations on the minimum principles for the exploration and production of hydrocarbons from shale formations using high-volume hydraulic fracturing.
A 2016 government report on the UK shale gas sector was finally made available in 2019 after a three-year legal battle to make it public, but with three-quarters of its pages blacked out. The unredacted paragraphs said that the government was "undertaking crucial work on communications to increase public acceptability of shale." In March 2019, the High Court found the UK government's policy was unlawful and failed to consider the climate impact of shale gas extraction.
In November 2019 the government announced "an indefinite suspension" to fracking, after a report by the Oil and Gas Authority (OGA) said it was not possible to predict the probability or size of tremors caused by the practice. Business Secretary Andrea Leadsom said that the suspension might be temporary - imposed "until and unless" extraction is proved safe. As of February 2022, the two Cuadrilla wells in Lancashire, which had been out of operation since the ban, were supposed to finally be plugged and decommissioned.
The Eden Project in Cornwall began drilling and fracking two geothermal wells in 2021 as a source for a geothermal power station. heating of the artificial biomes using geothermal hot water at 85 °C began in 2023.
By mid March and 4 weeks into the 2022 Russian invasion of Ukraine the CEO of Cuadrilla asked the government to keep the wells open for energy security.
On 8 June 2026, Lancashire County Council officially served an enforcement notice, ordering Cuadrilla to completely restore its Preston New Road fracking site, near Blackpool, to farmland, by the end of the year.
Regulation
Several government agencies, departments and one government company are involved in the regulation of hydraulic fracturing in the United Kingdom: the North Sea Transition Authority (NSTA), the Department for Energy Security and Net Zero (DESNZ), the local council planning authority including the Minerals Planning Authority (MPA), the Health and Safety Executive (HSE) and one of four environment agencies These environmental agencies are: the Environment Agency for England; Natural Resources Wales; the Scottish Environment Protection Agency (SEPA) for Scotland, and; the Northern Ireland Environment Agency (NIEA) for Northern Ireland.
Licences and permits Before onshore hydraulic fracturing can begin, an operator will have obtained a landward licence, known as a Petroleum Exploration and Development Licence (PEDL), from the OGA.
A series of steps are then taken to obtain permissions from the landowner and council planning authorities. The operator then requests a permit from the Minerals Planning Authority (MPA), who together with the local planning authority, determine if an environmental impact assessment (EIA), funded by the operator, is required.
Up to six permits, constituting the Environmental Permitting Regulations (EPR) 2010, two permits "under the Water Resources Act 1991" and one permit "under the Control of Major Accident Hazards Regulations 2015" are obtained from the appropriate environmental agency, to ensure that onshore hydraulic fracturing operators fulfil strict environmental regulations.
The role of the Health and Safety Executive (HSE) is to focus on the design and integrity of the well, using an independent expert known as the 'well examiner'. The EA and HSE together will "inspect the next series of hydraulic fracturing operations in England and Wales."
A hydraulic fracture plan (HFP) is required for both conventional hydraulic fracture well stimulation and unconventional high volume hydraulic well stimulation. The HFP is agreed with OGA in consultation with the EA and HSE. Hydraulic fracturing consent (HFC) is granted following an application to BEIS, to be reviewed by the Secretary of State, and; comply with requirements to mitigate any seismic risks.
In October 2022, British Prime Minister Rishi Sunak reinstated England's fracking ban moratorium after it was briefly lifted by his predecessor Liz Truss.
Permitted chemicals