Over the course of six episodes they’ll take viewers on a guided tour of the production lines that operate 24 hours a day to make some of the UK’s favourite products on an industrial scale. Every morning in Britain we get through over one and half million bowls of cornflakes. In Cereal, Gregg will be on the factory floor at Kelloggs’s biggest factory near Manchester, which is the single largest producer of breakfast cereal in Europe. We’ll see Gregg receiving corn fresh off the boat from Argentina and following its journey as it is cooked, milled and flavoured to become Crunchy Nut Cornflakes. He'll discover how the factory can produce more than a million boxes of cereal every 24 hours and distribute them all over the UK, Europe and across the globe, as far away as Malaysia. Meanwhile Cherry Healey looks beyond the factory floor to find out why many vitamins are added to breakfast cereal and the resultant health benefits of doing so. She also discovers the effect that skipping breakfast has on our cognitive function and she follows the production of the nation’s best-selling cereal, Weetabix, learning how every single grain of wheat that is milled for these wheat biscuits is grown within a 50 mile radius of the factory. And historian Ruth Goodman looks at how breakfast cereal was invented as a healthy alternative to the average Victorian household’s mind-boggling breakfast feasts. Ruth will also discover the effect of nostalgia, with the six top selling cereals in the UK today all invented more than 30 years ago.

Gregg Wallace follows 27 tonnes of potatoes from a farm in Hampshire through the largest crisp factory on earth, as they are peeled, sliced and fried to make more than five million packets of crisps every 24 hours. Once the crisps are flavoured, they are put into bags in one of the craziest rooms Gregg has ever seen, with over 100 machines that can fill hundreds of thousands of bags every hour. Greg discovers how each bag is filled with nitrogen to keep the crisps from going stale and how they are distributed all over the UK - and even as far as the Costa del Sol to satisfy the local expats. Meanwhile, Cherry Healey discovers the secrets of perfect crisp potatoes which are special varieties grown exclusively to make crisps, as well the surprising ways that our brain can be tricked into thinking a crisp is much crunchier than it really is. She also finds out how more than a third of savoury snacks consumed in the UK are made from corn and follows the production of Monster Munch, where the factory transforms 96 tonnes of corn into 12 million monster feet every single day. And historian Ruth Goodman investigates who really invented the crisp - was it the Americans, as is often cited, or the British? Ruth cooks up the earliest known recipe for crisps to uncover the truth. She also discovers how crisp wars between crisp manufacturers erupted in the 1960s and how in the 1980s, they tried to woo customers with strange innovations such as hedgehog crisps. Their determination fuelled our demand and today we get through over a half a billion crisps every 24 hours.

Gregg Wallace helps to unload 27 tonnes of dried haricot beans from North America and follows them on a one and a half mile journey through the largest baked bean factory in the world, which makes more than three million cans of beans every 24 hours. Gregg discovers how a laser scrutinizes every single bean, how the spice recipe for the sauce is a classified secret known only by two people, and, most surprisingly, how the beans are cooked in the can in a room of giant pressure cookers - not baked at all! Meanwhile, Cherry Healey follows the journey of her discarded baked bean can through a recycling centre and on to the largest steelworks in the UK, where she watches a dramatic, fiery process that produces 320 tonnes of molten steel - enough to make eight million cans. She also takes a can that is 14 months after its best before date to a lab at the University of Coventry and is amazed when tests reveal it has the same Vitamin C levels compared to fresh tomatoes. The lab also prove that a 45-year-old tin of Skippers is still fit to eat. And historian Ruth Goodman reveals that in the early 19th century, malnutrition killed more than half of all British seamen, and how tinned food was invented to improve their nutrition and prevent them developing scurvy on their long voyages at sea. Ruth also relates how Henry Heinz first marketed baked beans in the UK in the early 1900s and made them a family favourite. Today, we get through more than two million cans of them every day.

Brompton’s bicycle factory in West London is the largest in Britain, producing 150 of its distinctive folding bicycles every 24 hours. In the fourth episode of Inside the Factory Gregg joins a multi-stage manual production line to make his very own bike. He’ll learn how to put together 1200 individual parts. He'll also attempt to braze a bike frame together using extreme heat of a thousand degrees, a skill that takes years to master. He’ll visit a leather saddle maker in Birmingham that’s been making saddles for 150 years and discover how they use cowhide from UK and Ireland cows because the cold weather means they have thicker skins. Meanwhile, Cherry Healey gets some tips from Cycling Team GB to help us all improve our pedal power. She also learns how to paint a bike frame fit for the British weather using an electro-static charge and a 180 degree hot oven. Cherry also investigates why cyclists and trucks are such a deadly combination: in London alone there have been 66 fatalities since 2011 and half of them were collisions with a truck. And historian Ruth Goodman reveals that folding bikes date back to the 1870’s, and how 70,000 folding 'parabikes' were manufactured during World War II, some of which played a role in the D-Day landings. She’ll also find out how the invention of the safety bicycle in the late 1880’s was used by Suffragettes to ride to rallies and spread the word in their fight for equality.

In the fifth episode of Inside The Factory we see Gregg Wallace helping to unload a tanker full of sugar from Norfolk and follows it through one of the oldest sweet factories in Britain - Swizzels in Derbyshire - to see how over 500 workers, as well as some mind-boggling machines, transform it into over a hundred million individual sweets within just 24 hours. He'll discover how this factory that produces Lovehearts could be the most romantic place to work in the world and how the words on Lovehearts have evolved over the decades. Gregg will also find out how they make 5,000 Fizzers a minute using a tablet pressing machine that uses three tonnes of pressure to create each sweet, and he meets the man in charge of making three quarters of a million Fruity Pop lollies every day. Meanwhile Cherry Healey is let inside the research and development department and experiences for herself how hard it is to come up with a new product - plus she researches how the country you’re from has an impact on the sweets you like. She also finds out how they put the letters in seaside rock and is given special access to the Fisherman’s Friend factory in Lancashire to discover how a local family turned a niche product into a worldwide success. And historian Ruth Goodman investigates how sweets were first invented and discovers that, in the Middle Ages, they were used as a medicine and thought to reduce flatulence. She’ll also find out about the human cost of Britain’s sweet tooth in the 18th century and how an abolition movement instigated a sugar boycott which helped to end the slave trade.

Gregg Wallace joins a human production line in the largest sports shoe factory in the UK to see how they produce three-and-a-half thousand pairs of trainers every 24 hours by sewing 32 million individual stiches and using 140 miles of thread. He makes his own pair of shoes and discovers how they put together 27 different pieces made from eight different materials which require auto and manual stitching and finishing with a 'roughening' robot and a hot oven. He also meets the man who comes up with new designs, including trainers inspired by the three most popular pub names in England. Meanwhile, Cherry Healey gets hands on in a tannery to help them process thousands of rawhides into finished leather for the nation's shoes, and finds out how a ballet shoe company painstakingly turns 37,000 square meters of satin into a quarter-of-a-million ballet shoes - some of which only last for one performance. She also gets to design her own court shoes at Cordwainers College in London, where she learns how to turn creative ideas into commercial products - last year, sales of women's designer shoes topped £532 million. And historian Ruth Goodman reveals how, when the sewing machine was first introduced into shoe factories in the mid-19th century, traditional shoemakers went on strike, rebelling against joining a restrictive production line. She also traces the surprising origins of the humble trainer to the back streets of Bolton, where Joe Foster invented his running spike in 1895, above his father's sweet shop, and discovers that Reebok trainers were originally British.