In 2022, the former director general of MI5, Baroness Eliza Manningham-Buller cogently said: ‘food is part of our national security’. [1] The concept of food security as national security has since become commonplace in policy debates.
A nation that cannot reliably grow at least some of its food is inherently vulnerable, as food shortages can lead to instability and revolt. But if we are to have a serious conversation about food security, we need to acknowledge the importance of fertilisers.
Nitrogen leads to plant growth and higher yields, phosphorus is vital for root development and drought resistance, and potassium improves crop quality. [2] Fertilisers with these macronutrients provide the foundations of modern crop production. They have enabled the lives of several billion people, who otherwise would have died prematurely, or never been born at all. [3] According to Vaclav Smil, the foremost analyst of global food systems, nitrogen fertilisers alone help to produce half of global food supply. [4]
Domestic fertiliser production is harder than it seems
The problem of our dependence on manmade fertiliser is both environmental and strategic. Fertiliser production is energy intensive, requiring raw materials such as natural gas, as well as potash rock and phosphate rock, none of which we have here in the UK. This means that our food security relies on carbon-intensive energy sources and geopolitically sensitive supply chains, as shown in the current conflict blocking the Strait of Hormuz, through which around 30% of global fertiliser supplies flow.
The UK’s domestic fertiliser production capacity has declined in recent years, the implicit assumption being that global markets would always fill the gap. That assumption has not aged well. But rebuilding is not straightforward either.
Yorkshire has vast quantities of polyhalite, a naturally occurring multi-nutrient mineral containing potassium, calcium, magnesium and sulfur that can improve nutrient use efficiency and reduce environmental impact. [5] Britain also has the potential to be a world leader in green and blue ammonia production from alternative energy sources, but needs serious investment to achieve this ambition.
Farming without fertilisers?
Why not simply farm without fertilisers? We are sympathetic to that ambition in the long run. Organic and regenerative methods have great merit but cannot alone feed our population at scale in the near term. Moreover, agricultural land is finite and faces competing demands: housing, data centres, solar farms, wind turbines.
The idea that we can simply cut fertiliser use down to zero while maintaining food security requires a plan we do not yet have. We need to learn the lessons from Sri Lanka. An overnight ban on manmade fertilisers five years ago triggered crop failures within months and contributed to a broader economic and political collapse. [6]
Sequencing matters enormously. Labour knows this: its food strategy is rightly long-termist. Fertiliser policy should be too.
Key policy priorities
Firstly, we need to be pragmatic, not sentimental. In the short to medium term, fertilisers remain indispensable. Acknowledging this provides certainty to UK farmers and food producers, enabling investment and planning.
Second, we should treat polyhalite production as a genuine national strategic asset.
Third, we should pursue a strategic partnership with Canada on potash supply. Canada holds some of the world's largest reserves, and a formal bilateral arrangement could reduce our dependence on hostile or unstable exporters.
Fourth, we should use gene editing legislation boldly. By developing crops that require less fertiliser, the UK could position itself at the forefront of a new and genuinely environmentally friendly farming revolution.
None of this happens without joined-up government. Fertiliser security sits at the intersection of Defra, the Department for Business and Trade, and the Department for Science, Innovation and Technology. These departments must work to a common framework, treating fertiliser supply with the same seriousness we give to energy or defence procurement. Food security is national security. But national security requires securing the inputs that make food possible in the first place.
[1]NFU Online, ‘Food is part of our national security says former MI5 Director General’, 29 November 2022.
Available at: https://www.nfuonline.com/news/food-is-part-of-our-national-security-says-former-mi5-director-general/
[2] Organisation for Economic Co-Operation and Development, ‘Understanding the resilience of fertiliser markets to shocks: an overview of fertiliser policies’, June 2024.
[3]Our World in Data, ‘How many people does synthetic fertilizer feed?’, 7 November, 2017.
Available at: https://ourworldindata.org/how-many-people-does-synthetic-fertilizer-feed
[4] Vaclav Smil, ‘Nitrogen cycle and world food production’, World Agriculture, 2011.
Available at: https://vaclavsmil.com/wp-content/uploads/2024/10/smil-article-worldagriculture.pdf
[5] Springer Nature, ‘Polyhalite nutrients driving balanced crop nutrition and sustainable agricultural productivity’, 21 February 2026.
Available at: https://link.springer.com/article/10.1007/s44378-026-00179-z
[6] Alan Bullion, ‘Sri Lanka shows phased transition to organics and biofertilizers is vital’, 1 August 2022. Available at: https://www.spglobal.com/energy/en/research-analytics/sri-lanka-shows-phased-transition-to-organics-biofertilizers
