Cadbury's Double Decker
The Double Decker was introduced in 1976 and originally had raisins in the bottom layer.
In 1987 the wrapper received a complete overhaul, introducing the orange/purple colour scheme still in use today. The lettering was made rounder and lowercase, while the Cadbury's logo now sits inside a slanted box.
For the new millennium, the wrapper received yet another overhaul. The lettering was now entirely lowercase, and given a large purple outline, and the Cadbury's logo was removed from the box.
Cadbury Double Decker
After Cadbury's became Cadbury at the end of 2002, some edits were made to the wrapper again. The font is now entirely capitalised again, and the Cadbury swirl was added.
As Cadbury was phasing out the swirl logo, new branding was introduced, giving the bar it's first overhaul in 10 years. The "Double" portion of the name is now lowercase and the orange/purple design no longer appears textured.
In 2016, a slight redesign was introduced, with new fonts for both parts of the logo and the "double" now slightly overlapping in a similar style to the 1987 logo.