Gregg Wallace receives some tea leaves from Kenya and follows them through the factory that produces one quarter of all the tea drunk in Britain.

Gregg Wallace is at the world's largest dried pasta factory in Italy, where they produce 150,000 kilometres of spaghetti each day.

Gregg Wallace follows the production of chocolate digestives and discovers that we are all eating them the wrong way up.

Gregg Wallace explores the Grimsby factory that processes 165 tonnes of fish a week and produces 80,000 cod fish fingers every day.

Ruth Goodman investigates the origin of Worcestershire sauce, as told by Mr Lea and Mr Perrins.

Gregg Wallace explores Ribena's Gloucestershire factory. Meanwhile, Cherry Healey is in the lab figuring out why fizzy drinks are so appealing.

How a factory in Stoke-on-Trent produces 250,000 little cherry bakewell tarts every day - from what makes a shortcrust pastry 'short' to the team of 12 precisely placing the cherry on top of every one by hand. How to swerve a soggy pastry bottom when baking pies and tarts at home. How almonds are roasted and milled into almond butter ready for toast. The origin story of frangipane, the fragrant almond filling used in cherry bakewell. How the modern cherry bakewell actually descends from a mistake.

How a factory in South Shields produces 650 water-resistant waxed jackets a day - from 500-metre-long rolls of undyed cotton, to dipping the finished fabric into baths of heated wax, to assembling each jacket from 23 pieces. How a breathable membrane is key to allowing sweat to get out while keeping water from getting in. How a simple wooden stick is transformed into a top-notch umbrella using saws, pliers, and needle and thread - techniques barely changed in 150 years. The history of seamen adapting oil-covered sail cloth into garments.

How a factory in France produces 336,000 croissants every day - from the 21 tonnes of butter, to the 83-year-old strain of yeast that packs a flavourful punch, to the layering of very thin slices of butter between sheets of dough to create the famously flaky texture. How croissants are best served - and eaten. How 'concentrated' butter produced in north Wales enhances the shelf life of croissants. The history of the croissant, thought to originate from 17th-century Austria, and emerging in its modern French form as late as 1906. How bread played a vital role in the French Revolution.

How a factory in Leeds produces 600 bouncy beds every day - from making steel into springs, to their placement in individual pockets and covering in natural fibres like hemp and wool designed to wick away sweat. How a short, twenty-minute sleep improves reaction times. How wool is shorn from sheep, and its inherent anti-bacterial and fire-retardant properties that make it well suited to mattresses. How the modern spring mattress evolved. How a famous Scandinavian-inspired home store is responsible for popularizing the duvet.

How a bakery in Cornwall produces 180,000 Cornish pasties a day. There are rules: A Cornish pasty must be made in Cornwall; the filling can only contain onion, potato, swede, beef and some seasoning; and each ingredient must be cooked from raw within the pastry parcel. The versatility of onions, and how they make us cry. How anaerobic digestion turns food factory waste into electricity. Challenging the pasty's origin story. How importation of pepper eventually transformed it from a precious commodity to a spice that everyone could afford.

How a foundry in France produces a cast iron pot every five seconds - from the arrival of 20 tonnes of crude iron right through to brightly coloured orange casserole dishes. How a South African iron ore mine - one of the largest in the world - produces a staggering 670,000 tonnes every day. The science behind cooking the perfect casserole - more cooking time isn't always better. The history of one-pot cooking to prepare simple meals, from communal ovens to 1970s slow cookers. How casting iron in sand moulds democratised the kitchen through affordable cookware.

How a factory in Wigan produces two million tins of soup a day. Vegetable soup is followed from a pea harvest in Yorkshire right through to the finished soup going into cans and being dispatched. How the vitamin content of frozen vegetables can greatly exceed that of fresh. How a spinach soup based on a 17th-century recipe doesn't much resemble soup as we know it today. The history of the soup kitchen.

How a factory in Ireland produces 540,000 bottles of liqueurs a day. From grain, to barrel aging, to mixing cream and whiskey together, the show traces the production of a cream liqueur over the span of three years. How Ireland’s bottles and jars are recycled at a plant processing 500 tonnes every day. How all alcoholic drinks - not just aperitifs - stimulate appetite. The rules for producing and labelling whiskey, bourbon, and blends. How monks invented liqueurs. The impact of modern distillation methods on traditionally made alcohols like Irish whiskey.

How a factory in Essex produces 400,000 cereal bars a day - from nuts to cranberries and sultanas to puffed rice, with a carefully balanced blend of honey and glucose binding it all together for the ideal texture. How macadamia nuts are harvested in South Africa, and shelled under extraordinary pressure. The scientific distinction between botanical nuts, legumes and drupes. The history of Britain's cereal bars, including one Kendal Mint Cake snack bar made popular by famous explorers Ernest Shackleton and Sir Edmund Hillary.

How Polos produce 32 million mints every day in York - part of the 19,000 tonnes of mints consumed every year in the UK. The largest sugar beet factory in Europe. How one of the last surviving peppermint farms in the UK harvest their crop. How clever marketing persuaded people to buy minty mouthwash.

Gregg Wallace visits Britain's largest bicycle factory, which produces 150 folding bikes every day, and joins a production line to make his own bike.

In this Christmas special, new presenter Paddy McGuinness and Cherry Healey visit a chocolate factory in Belgium that produces four million chocolate seashells every day. Cherry Healey is also in Belgium, learning the secrets of white chocolate production at the biggest chocolate factory in the world, and Ruth Goodman is in a city with a familiar-sounding name, Saint Niklas, exploring the European origins of Santa.

Gregg Wallace visits the UK's largest sports shoe factory to see how they produce 3,500 pairs of trainers every day.

Paddy McGuinness makes a wonderfully nostalgic trip to the Warburtons factory in his hometown of Bolton where, thirty years ago, he had a Saturday job cleaning the machines. Meanwhile, Cherry Healey discovers how waste bread is turned into beer, and historian Ruth Goodman reveals why white bread was banned during World War Two.

How Woodmansterne produces 35 million greeting cards a year in Watford - from sketching a card design, to creating an aluminium plate for printing, to guillotining the sheets into cards and the final shipping process. Creating a vegan Christmas feast. The history of the year Christmas was cancelled.

How JCB make as many as a hundred iconic yellow diggers every single day in Rocester, Staffordshire, requiring just 45 hours to make a digger from scratch, and consuming 650 tonnes of steel, 170,000 bolts, 5,000 litres of paint and 236 miles of wiring each week.

How a 32-acre site in Somerset makes 1.2 million Henry vacuum cleaners every year.

Gregg Wallace visits a bootmaking factory in Wollaston, Northamptonshire to follow the production of a pair of Dr. Martens, while Cherry Healey gets to grips with the machines that make shoelaces.

How a family-run factory in rural Aberdeenshire churns out fifty thousand litres of dairy ice cream every day. How best to stop 'brain freeze.' How sprinkles are made. How ice cream vans made soft whip a favourite on Britain's streets.