The red double-decker bus is a global icon. They carry millions of passengers every day across the capital and are as synonymous with London as Tower Bridge and Buckingham Palace. Now, Gregg Wallace has special access to a factory in Scarborough, Yorkshire where they build this famous people mover. But the bus that Gregg is helping to produce is a little bit special, because it's fully electric.

Gregg helps the factory across all stages of the bus's construction, including operating a crane to lower the bus's steps in place, adding the anti-slip lino, riveting and gluing the walls and wiring the electrics - before taking on the nerve-wracking task of driving the finished bus out of the factory.

Meanwhile, Cherry Healey visits a bus windscreen factory where she gets to grips with the construction of tough laminated heated windscreens. And in the main bus factory, she helps to give the bus its bright red coat of paint. She also visits an offshore windfarm to learn how turbines convert wind into watts that could one day power the electric buses.

Historian Ruth Goodman learns about London's earliest double deckers and the vital role they played in the First World War.

Gregg Wallace explores the Vale of Mowbray pork pie factory in Northallerton, Yorkshire, which began making pork pies in 1928. He visited the factory in May 2022, following production of their 75g snack-sized traditional pork pie – of which they make 425,000 every week.

Cherry Healey reveals hacks for the perfect vegan shortcrust pastry, makes piccalilli as a pork pie accompaniment, and learns how to drive one of the HGVs that transport food products every day.

In Cornwall, Ruth Goodman fishes for the history of one of Britain's most unusual pies, the star gazey pie, and she explores the story of powdered egg during the Second World War.