Is Inside Greggs: 24/7 coming back?

In this programme we explore the phenomenon of Greggs. With hundreds of new shops opening up and down the country, over 1.5 billion pounds in revenue, a sell-out clothing line and a huge celebrity endorsement, Greggs is now a legendary part of popular culture. But why? Food critic and food lover Grace Dent traces the history of the company to figure out the secrets of their extraordinary success.