Campaign visited London's Museum of Brands, Packaging and Advertising to discover what drives successful heritage brands and learn how they have reimagined themselves in order to remain relevant today.
Museum of Brands chief executive Chris Griffin believes trust is the key to maintaining consumer loyalty.
He said: "The more trusted the brand, the more likely it is to survive. That's why I think if you suddenly take the brand in a new direction, you can lose the customer completely."
One brand featured in the documentary is the popular confectioner, Cadbury. Founded almost 200 years ago, it is still the nation's favourite chocolate brand, leading the market with a 32% value share of the chocolate category.
Speaking to Campaign at Cadbury's Bournville heartland, Benazir Barlet-Batada, brand equity lead - Cadbury UK & Ireland, Mondelez International, said: "Cadbury's been around since 1824 and today it is one of the top five food brands in the UK."
In reference to the brand's takeover by US food giant Kraft in 2010, she added: "Since the acquisition, the brand has actually grown by 27% because we have committed and remained true to its heritage."