An employee monitors foil-wrapped Cadbury Creme Eggs as they move along the production line at the Bournville Cadbury factory. Photo / Getty
In Bournville, a small town on the south side of Birmingham, purple arrows direct visitors from the station to Cadbury World, a chocolate lover's paradise that would make even Willy Wonka envious.
But the real magic happens in a small laboratory in an unassuming office block just in front of the factory.
Here Cadbury's 200 master chocolatiers and scientists come up with new lines and flavours for millions of chocolate lovers across the world.
At the head of this global, yet secretive, operation, is Tom Dingley, who joined Cadbury nine years ago before the brand was taken over by US food giant Kraft.
"It's hard to get your head around the fact that this little place in Birmingham actually makes the chocolate that people eat as far as Brazil, India and Australia," says Dingley, who studied biosciences at Birmingham University, before joining Cadbury as a graduate in 2006.
He's the man behind recent innovations including the Cadbury Dairy Milk Bubbly bars and the Marvellous Creations lines - chocolate bars with fillings such as jelly popping candy and banana caramel crisp.
"These tables were just laden with sweet colourful, popping and fizzy things when we were designing Marvellous Creations. The idea was to make chocolate more fun for families - like having fireworks in your mouth," says Dingley. "The line has become really successful and in Australia there's a really big range".
Every chocolate product starts life in Bournville in the research and development lab set up by Mondelez in 2012 with a £17m investment.
New chocolate ideas are sketched and designed in the lab, before being moulded and packaged in a small test factory next door, to which The Sunday Telegraph was not allowed access ["top secret, I'm afraid," says Dingley].
Once approved, the chocolate designs are given the green light to be manufactured in local factories across the world, from North America to Asia. While the fundamentals of the chocolate are essentially the same, flavours are sometimes tweaked to country preferences.
In Australia, for example, tropical flavours are more popular, and Cherry Ripe, is a top seller.
In the UK, all Cadbury products are made at Bournville. The factory, which is open every day except Christmas Day, pumps out 5.5m blocks of chocolate every 24 hours, 1m Wispa bars, 1.2m creme eggs and 400m Milk Buttons, as well as other lines such as Roses and Heroes.
Kraft now operates as Mondelez in the UK, employing around 2,000 people in Bournville at the factory, office headquarters and Cadbury World.
Bournville has been the home of Cadbury's chocolate since the 1870s, and has an extraordinary history. Before the Cadbury brothers turned it into the home of their eponymous brand, Bournville was essentially green space four miles outside Birmingham.
The brothers, who inherited the business from their father, built a factory on the site and houses for the workers. Passionate about social reform, they wanted the Bournville estate also to include parks, recreation grounds and open space to give their workers a healthier environment.
Over the next century, Cadbury continued to grow rapidly, listing on the stock exchange in the late 1960s and merging with Schweppes - although the two later split.
In 2010, Cadbury was controversially taken over by US food giant Kraft in a hostile pounds 11.5bn deal. Already unpopular with Britons, matters were made worse when Kraft shut a factory near Bristol, despite promises during the deal that it would be kept open.
In 2012 the confectionery business of Kraft was spun off into a separate company named Mondelez, which also owns brands including Belvita, Maynards, Philadelphia, Ritz, Kenco and Milka.
The sweets and biscuits are made in Sheffield, and the company also owns a large coffee plant in Banbury, Oxfordshire, which produces 100m jars of instant coffee brand Kenco each year.
Since taking over the Cadbury brand, Mondelez has also been no stranger to controversy. Consumers complained when it rounded the corners on the chunks of Dairy Milk, shrinking the new bars by
four grams but taking zero off the price. Then followed news that Dairy Milk chocolate coins were being discontinued. The company said the seasonal coin business had become less profitable as people favoured rival, cheaper versions.
There was further outrage after it was recently revealed that the creme egg chocolate shell, which used to be made from Dairy Milk, had been replaced with the more basic Cadbury chocolate, typically found in Crunchies and Starbars.
The recipe change was undertaken at the R&D centre here. While Dingley says he is aware of the controversy, he maintains there is little change to the taste and quality. "When we do the development work, we always make sure it tastes great. That's the main thing that is important to us. There are sometimes technical reasons to use different types of chocolate; perhaps some types are better suited than others. But when you've got a brand that's as loved as Cadbury, people love talking about it."
Despite these recent controversies, people clearly still love Cadbury's chocolate. Mondelez's Cadbury Dairy Milk is still the most popular chocolate bar in terms of sales in the UK, according to data from market analysts IRI. Sales hit £491m in the year to the end of August last year. That was a 3.5 per cent rise on the year before and far outstripped the smooth bars of Galaxy, its closest rival, which sold £213m, a 5 per cent fall on 2013.
In fact, people love Cadbury so much that talk of a Dairy Milk shortage is enough to send people into a frenzy.
There was panic among British expats across the Pond when it was announced this year that American brand Hershey's had brought a lawsuit effectively barring the import of Cadbury's products and other chocolate made in the UK.
British shop Tea & Sympathy, based in Manhattan's Greenwich Village, broke the news on its Facebook page, saying that "due to legal action we can no longer import the real Cadbury from England".
Almost 38,000 people have since signed a petition to boycott Hershey's in the US. Mondelez says the legal technicalities means that it can't comment on the issue.
"Cadbury has been a very successful brand for a very long time," says Stuart Roper, a professor in marketing at Bradford University School of Management. "The company has some great brands that we associate with childhood, such as Curly Wurly. This gives people a real emotional connection with the company.
"Having said that, a lot of the brand extensions that have come in recently are not so UK centric. I'm not sure teenagers would be so familiar now with the Cadbury heritage, and they might not have the same emotional attachment."
In Bournville, Dingley says the team are constantly working on new products and flavours to satisfy global tastes, and he is currently working on seven new ideas.
Despite constantly tasting chocolate all day, he says he still loves the taste and will often snack on more chocolate when he comes home. His favourite line is the Bubbly bar.
"One thing I certainly never get sick of is melted chocolate," he says, preparing to demonstrate how Cadbury makes ones of the 47m Easter eggs it sells each year.
In basic technique, little has changed in more than a century.
A bowl of hot melted chocolate is tipped on to a marble-topped counter, which Dingley continually spreads and moves around to cool - or "temper" - to 26C while keeping the consistency light. If you go too slowly, the chocolate sets.
"There is no way of avoiding tempering," says Dingley. "In artisan chocolate shops, this is what they're doing behind the counter. Obviously we have machinery now which constantly tempers on an industrial scale, but when I'm developing new lines, this is what I do."
He's helped by 20-year-old Martin Raybould, who joined Mondelez on an apprenticeship scheme in September. Mondelez takes on two apprentices from the cookery course at University College Birmingham each year.
The apprentices are trained in all aspects of chocolate making for two years, with the chance of a job at the end of it.
The cooled chocolate is poured into an Easter egg case, where it is then banged on the table to remove any air bubbles, and poured back onto the marble top, leaving a chocolate shell, which is left to cool and set for an hour.
Dingley says he couldn't imagine doing another job. "When I go abroad, it's mind blowing to see chocolate on shelves as far as Canada and Australia that a few months ago were only a pencil sketch."
A live cook-off featured ox heart, wapiti, wild boar and plenty of edible wildlife.