Britain last produced all its own food at the end of the eighteenth century. Since then, our levels of food security - growing what we eat ourselves - have risen and fallen depending on world markets, domestic politics, and war. Now, in an unstable world, many people in farming argue that food security should once again be a real concern. But is that just a marketing ploy? In episode 8 of Against the Grain, Charlotte Smith debates the issue with farmers' leaders and economists.

Producer: Chris Ledgard.