Food lover Grace Dent explores the phenomenon of Greggs, and its place in popular culture, visiting a pizza centre, the shop's original location and meeting the company's CEO.

Grace Dent gets exclusive access to Greggs's secret innovation centre at their HQ, receiving a sneak preview of new product ranges, and also looks at the famous vegan sausage roll.

Behind the scenes of the popular high street bakery chain during the festive period.