The UK's food self-sufficiency has fallen over the past 10 years as the country has become more reliant on imports, according to the Soil Association's report An Inconvenient Truth About Food, compiled by researchers at City University, London.
Global market volatility, the scarcity and increasing cost of oil and the vulnerability of food and farming systems to climate change had combined to threaten the country's food security further, it said. The UK is currently 60% self-sufficient in food, according to Defra.
The new food plan needed to outline how to improve the nation's diet and cut greenhouse gas emissions by 80%, the researchers said. To achieve, this the government should incentivise producers to use low-carbon farming practices and soil-management techniques as part of good agricultural and environmental practice under the Single Payment Scheme, they added.
Health and farming policy objectives also needed to be brought more closely together to help prevent premature deaths and the obesity crisis deepening.
The report praised projects such as Rosie Boycott's initiative to turn 2,012 pieces of derelict land in London into food growing spaces, and called for more local food hubs. It also proposed clear and easy-to-understand carbon labels to allow consumers to select the least environmentally damaging food.
"Action at every level - government, local communities and individuals - will be essential if the necessary changes are to be put in place," said Soil Association director Patrick Holden.
"We have to act now to start cutting greenhouse gases. Diet-related ill-health is already causing misery to many and costing the UK billions. And we could face serious price and supply problems with the fossil fuels our current farming systems rely on well before 2020."