The briefing suggests that allotments and gardens can also provide clues on how we can produce ample, healthy food in a sustainable way.
Studies on the productivity of allotments show that they can produce the equivalent of 35 tonnes of food per hectare. The food grown on allotments is healthy, local, pesticide-free, creates zero waste and involves no packaging.
Currently, an estimated 90,000 people are on waiting lists for an allotment in Britain.
The briefing argues that by leaving the Common Agricultural Policy, the UK could divert some of the £3.5 billion currently given out in farm subsidies to purchase land for allotments and invest in making small-scale, sustainable farming financially viable.