In this final episode of the series Heston Blumenthal tackles the challenge of making the ultimate Christmas dinner. In the grownup world, Christmas has lost some of its wonder. Heston wants to change that and plans to create a supersized festive food adventure, to be enjoyed by a group of adults who normally have to work on Christmas Day. Heston visits Hampton Court, and discovers that instead of turkey, our ancestors preferred to eat pig's head. Heston wants to put this on the menu alongside edible Christmas decorations. The final part of Heston's historical yuletide wonderland takes inspiration from the Victorian period, and their love of Christmas pudding. Heston makes the biggest Christmas pudding ever - one that's large enough to step inside.

Heston celebrates the packed lunch by building a super-sized sandwich with unexpected 'rogue' fillings. There's also the world's biggest crisps and the world's biggest KitKat. Heston fills an entire theme park with nostalgic packed-lunch favourites and invites disillusioned lunchers on a surprise trip. His giant super-sized sandwich is big enough to feed a coachload of hungry adults and features syringes packed with injectable condiments. Heston summons the help of the Hula Hoops factory to create a packet of crisps so large that it's only accessible by ladder. And Heston builds a massive carton of the 80s classic Um Bongo, where adults pop their heads through huge foil circles and experience his tropical jungle scene.

Heston puts the fun back into pub grub, building a giant, edible pie and turning it into a fully functioning public house. He also makes a billiard table from cod, tartare sauce and pea mousse with pickled egg billiard balls.

Heston celebrates sweets, the greatest pleasure of childhood, by making his own Willy Wonka-inspired giant sweet shop.

Heston celebrates the tea break by making the world's biggest packet of biscuits, the largest pyramid tea bag and a drink containing the flavours of cucumber sandwiches and Victoria sponge. Tea and biscuits are still a staple of the nation, with 185 million cups washed down every day and nearly 90% of tea drinkers liking to dunk. But the tea break itself has died a death. Heston wants to bring it back to life and takes on the challenge of creating a packet of biscuits big enough to feed a whole town - so he combines the chocolate Digestive, HobNob and Gingernut biscuit with salted caramel and pockets of chocolate ganache.

Heston focuses on the ice cream van, a great British tradition that provided the soundtrack to so many childhoods, and the frozen treats every kid dreams of. But this wonderful British institution is in danger of extinction. In the 1970s, around 25,000 ice cream vans were on the roads - these days there are less than 5000. To help kickstart a revival, Heston plans to build the world's biggest ever 99 Flake, over five metres tall and weighing more than a ton, and serve it from the back of his own very special van to the town of Gloucester. He visits Walls and has Europe's biggest ice cream factory at his disposal. To make his chocolate flake, he ropes in the experts behind the Olympic stadium. Heston also turns the classic flavours of Twister, Cornetto, Feast and Calippo into paint balls that can be fired from specially designed cannons.

Heston tackles breakfast, creating the world's largest boiled egg and cereal on an epic scale. Then there's the full English - with a massive fry-up consisting of metre-long sausages, fried bread the size of carpet tiles, and jumbo baked beans. To top it all, Heston decides to make his breakfast for commuters, on his very own express steam train.