Aggregates firm Darrington Quarries Limited has been extracting magnesium limestone at Jackdaw Crag Quarry since the 1940s. The site covers 25 hectares and is in the green belt, about 1.5 kilometres to the south-west of the town of Tadcaster in Selby, North Yorkshire.
In 2016, North Yorkshire County Council granted the company planning permission for a six-hectare extension to the quarry, a development that was expected to yield about two million tonnes of crushed rock over a seven-year period.
But Samuel Smith Old Brewery (Tadcaster), a major landowner in the area, mounted a judicial review challenge to the decision. After failing before the High Court, the case succeeded before the Court of Appeal in March 2018.
Quashing the planning permission, Lord Justice Lindblom found that a senior planning officer's advice to councillors was defective in failing to make clear that, under paragraph 90 of the 2012 National Planning Policy Framework (NPPF) - now paragraph 146 of the revised 2019 framework - visual impact was potentially relevant to the question of whether the development would preserve the openness of the green belt.
The 2019 NPPF states that "the essential characteristics of green belts are their openness and their permanence".
Paragraph 146 lists mineral extraction among the forms of development that are "not inappropriate in the green belt provided they preserve its openness and do not conflict with the purposes of including land within it".
Overturning the Appeal Court ruling today, the Supreme Court found that, on a true reading of the NPPF, the visual quality of a landscape is not in itself an essential part of the openness for which the green belt is protected.
Lord Carnwath, who gave the court's judgment, noted that one of the primary objectives of green belt policy, since its inception, was "to prevent urban sprawl while keeping land permanently open".
The reference to "openness" in paragraph 90 (or 146 in the 2019 NPPF), he added, "does not imply freedom from any form of development" and "is not necessarily a statement about the visual qualities of the land".
Although visual impact may, in some cases, be relevant to the question of whether openness will be preserved, the weight to be given to it was "a matter of planning judgment, not law".
The judge added: "Paragraph 90 shows that some forms of development, including mineral extraction, may in principle be appropriate and compatible with the concept of openness.
"A large quarry may not be visually attractive whilst it lasts, but the minerals can only be extracted where they are found and the impact is temporary and subject to restoration.
"Further, as a barrier to urban sprawl, a quarry may be regarded in green belt policy terms as no less effective than a stretch of agricultural land."
There was, the judge ruled, no error in the planning officer's advice to councillors that, when considering the development's impact on openness, they were not required to take into account its visual impact.
There was nothing in paragraph 90 which expressly or impliedly rendered it mandatory for the councillors to take into account visual impact.
It was relevant that the proposal was for an extension of the quarry, rather than a wholly new project, and the officer did not suggest that visual impact can never be relevant to openness.
In his report, he did, in fact, give some weight to the visual effects of the development.
Lord Carnwath concluded that the relatively limited visual impact of the extension fell far short of being so obviously material to the question of openness that the failure to explicitly address it amounted to an error of law.
The appeal, brought by the council with the support of Darrington Quarries, was upheld and the planning permission restored.
Commenting on the case, planning solicitor Fergus Charlton, a legal director at law firm TLT, said: "The unanimous ruling has confirmed that the visual quality of landscape is not in itself an essential part of openness for which the green belt is protected.
"Openness is a counterpart of protecting against urban sprawl and is not necessarily a statement about the visual qualities of the land, nor does it imply freedom from all forms of development.
"The Supreme Court has helpfully given applicants and decision makers guidance on how to approach the assessment of harm to green belt openness.
"By ruling that openness is not necessarily a statement about the visual qualities of the land and ruling that protecting openness does not imply freedom from all forms of development, the court has confirmed that ‘not inappropriate’ development can proceed - reversing what was a worrying direction of travel."