Built, but not replaced: The policy failure behind the UK's ageing greenhouse sector

Societal Impact Statement Glass greenhouse horticulture is a highly productive but often overlooked component of UK agricultural, environmental and food policy, with significant potential to contribute to food security, public health and climate resilience. This paper argues that the ageing greenhouse estate reflects long‐term policy misalignment and the absence of conditions required for sustained investment and renewal. By reframing greenhouse production as infrastructure, it highlights opportunities to better align food production with energy systems, public procurement and spatial planning. Such integration could reduce import dependence, stabilise supply chains and strengthen links between domestic food production (incl. nursery plants) and public‐sector procurement, particularly within institutions such as the NHS and local authorities, supporting a more resilient and sustainable model of domestic production. Summary The United Kingdom's glass greenhouse horticulture sector is characterised by ageing infrastructure, with more than 70% of commercial greenhouse structures now over 40 years old and many constructed under technological and economic conditions that differ substantially from those of modern greenhouse production. This opinion piece argues that this is not simply the result of market conditions or technological change but the outcome of a long‐term policy trajectory in which food horticulture has been consistently included within agricultural frameworks without being recognised as a distinct, capital‐ and energy‐intensive system. A historical perspective is used to show how post‐war policy alignment enabled large‐scale infrastructure development, followed by a sustained period of underinvestment linked to policy frameworks that were poorly aligned with the capital, energy and infrastructure requirements of greenhouse production. Although recent policy developments signal renewed interest in controlled environment production, they remain insufficiently integrated. Reframing greenhouse horticulture as infrastructure provides a basis for aligning policy across energy, planning and procurement, and for addressing the risks associated with continued reliance on ageing systems and imported supply.