With the need to find ways to tackle the £169bn budget deficit, what would you do if someone offered a way to save £6bn this year rising to £10bn per year next year and ever after – with no public sector cuts or increases in taxes? And, what if this also boosted the green economy, creating jobs? And met consumer demand? And helped improve health?

Still interested? Well, the answer lies in what you eat and who grows it.

The negotiations producing the new Tory-Lib Dem coalition government have not yet agreed a position on food and farming. Despite lots of noise before the election, party manifestos were thin on the food and farming issue. Yet food's role in macro politics is staring us in the face. If the Cameron-Clegg marriage of convenience is to work, food will be a test case. A course charted by groups as diverse as the all-party environment, food and rural affairs committee and Chatham House's food working party suggests a new direction: investment in raising sustainable food production in the UK. This has the potential to reduce the yawning food trade gap, now at around £10bn. Growing more here makes financial not just environmental sense.

With the prime minister and his deputy both referring to the national interest, what better opportunity to reduce the costs of imports is there than beginning an ambitious programme for sustainably increasing UK food production? The forthcoming public sector squeeze will mean there is less money for food imports. Currency fluctuations already have added uncertainty to supply routes. Yet for years, UK production has been sliding badly, down by 18% since 1995. The UK now produces only around 60% of what it eats.

A new emphasis on raising UK food production requires some courage. To some it smacks of protectionism. To others, it just makes sense. It's not a question of growing more to keep other sources out, but of a new world in which everywhere must produce more food more sustainably to meet rising world needs. For a rich country like the UK not to produce the food it could is surely immoral. But the new production focus must not be at all costs; there's no point trying to grow bananas. Core foods ought to be the priority. The UK imports huge amounts of fruit and veg which could be grown here. Rebuilding horticulture is a priority.

In opposition, the Tories created an ambitious public sector procurement working party, chaired by Zac Goldsmith, now MP for Richmond Park. This had David Cameron's blessing. Public procurement, worth £2.2bn a year, can lead the way in linking better health standards for schools with UK production. The nutrient standards which began in 2008 for primary and 2009 in secondary and special schools need further nurturing.

A number of blocks to raising UK food production loom. First is the skills shortage. Try getting a pruner or grafter for an orchard. The UK can easily grow more of the vegetables and fruit, which nutritionists advise us to consume more of, yet only half of our veg and a 10th of our fruit consumption is grown here. This is folly but one pointing to a great opportunity. And look at the country of origin of catering staff. The food chain employs more than 3.2 million people. The last government's council of food policy advisers ended its second report on that note. Jobs, training and skills ought to be on the agenda of the new education secretary Michael Gove and business secretary Vince Cable, not just Caroline Spelman and Jim Paice at Defra .

The second block is vision. Ironically, the Labour government got there with its Food 2030 document, which was good in aspiration but silent on delivery mechanisms. Working out who needs to do what is the key priority. Getting the public and private sector to agree that sustainability ticks lots of boxes simultaneously: jobs, fiscal deficit, the environment and climate change.