Gregg Wallace is in Lowestoft, at an enormous factory where they produce 450 tonnes of frozen food each day. He follows the production of frozen potato waffles, from the arrival of 25 tonnes of potatoes right through to dispatch.

Gregg visits an enormous factory in Italy which produces 400,000 frozen pizzas each day. He mixes up a 450-kilogram batch of dough for the bases, enough for 180,000 pizzas, and watches as each one is stretched to exactly 26 centimetres in diameter.

Gregg Wallace and Cherry Healey get exclusive access to some of the largest food factories in Britain, to reveal the secrets behind food production on an epic scale. It's a 24 hour race from raw ingredients to supermarket shelf.

Gregg Wallace is in Germany, at a historic factory which produces 600,000 pencils a day. At materials intake he is astonished that the main material in a pencil is not lead, but graphite. He helps mix this with clay to produce a 250-kilo batch, enough for 200,000 pencils.

Gregg Wallace is in Gateshead, at a cheese factory where they produce 3,000 tonnes of spreadable cheese every year. He follows the production of jalapeno chilli flavoured cheese, from a 28,000 litre delivery of milk to 5,400 squeezy tubes.

Gregg catches up with the Essity paper mill in Manchester, which he visited back in 2018. The coronavirus crisis caused a huge spike in toilet roll sales, in March, the British public bought 145 million more rolls than usual.

Gregg reconnects with the Heinz baked beans factory in Wigan. The coronavirus crisis caused a massive spike in the sales of tinned goods, and the baked beans factory upped production to deliver almost 50 million cans in just one month.

Brits love a snack, and when the coronavirus crisis hit, sales of packet treats rose by 32%. Responding to the surge in demand, the factory made big changes to their production, sending out an extra 1,000 pallet loads of crisps every 24 hours.

The coronavirus crisis caused tea bag sales to soar, and the tea factory upped production to produce 109 million tea bags in a week, an increase of 28 million. Gregg looks back over his original visit to the factory and the whole production process.

Gregg Wallace visits the biggest cider factory in the world, which produces more than 350 million litres each year. The scale of production blows his mind, as at each turn he's confronted with huge machinery and incredible processes. Meanwhile, Cherry Healey explores how the factory is creating new orchards of a sweet apple variety called Scrumptious, and historian Ruth Goodman traces a Victorian apple-breeding boom.

To keep their feet nice and warm, the British spend almost 723 million pounds a year on socks. Gregg Wallace visits a sock factory in Leicester that produces one and a half million socks annually. Cherry Healey finds out what causes smelly feet, and Ruth Goodman steps back into the 1980s, when socks were at the height of fashion.