Grace grabs her hairnet and heads out to a vast Greggs pizza centre. The minus 20-degree freezer renders her speechless but she's soon warms up in the cabin of a vast truck delivering pizzas to Greggs shops across the south of England.

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.