Four chefs from past series return to show how far their food has progressed. They must cook for critics Grace Dent, Jimi Famurewa and Jay Rayner, and then prepare a festive feast.

Many of the products we use every day travel through dozens of machines. This series whisks us inside some of the world's largest factories to give us an inside peek at what exactly goes into mass-manufacturing our favorite items.

Many of the products we use every day travel through dozens of machines. This series whisks us inside some of the world's largest factories to give us an inside peek at what exactly goes into mass-manufacturing our favorite items.

Four chefs from past series return to show how far their food has progressed. They must cook for critics Grace Dent, Jimi Famurewa and Jay Rayner, and then prepare a festive feast.

Four chefs from past series return to show how far their food has progressed. They must cook for critics Grace Dent, Jimi Famurewa and Jay Rayner, and then prepare a festive feast.