Food allergies are on the rise, affecting 15 million people in North America and the UK. And drastic measures are being taken to protect the public, including banning peanuts from places where they were once commonplace: airplanes, sports arenas and schools.

Medical historian Matthew Smith, of Strathclyde University, explores the current obsession with allergies revealing why, in the space of a decade, the peanut has become food enemy number one.