First introduced in the UK in 1976, its name derives from the well-known double-decker bus, with the buses themselves sometimes appearing in advertisements for the product.

Originally the bar contained raisins within the base layer; however, consumer research in the mid-1980s led to these being removed and the current formulation being introduced.

[2] Television adverts in the 1970s featured Willie Rushton before a mascot named Dougie the Double Decker Dog was introduced.

[5] There also existed a 'Double Decker – Nuts' launched in 2004, which had the advertising slogan "crispy, crunchy, chewy and nutty".

This chocolate bar was essentially a Double Decker with nuts contained within the nougat layer; however, it has since been discontinued.