The nostalgic among us will no doubt welcome the news that Mars may resurrect Marathon on the back of the strong publicity the return of Opal Fruits has received.

Consumers love a blast from the past, but not as much as the confectionery manufacturers themselves, it seems. Mars is just the latest in a number of players to go retro. Nestlé led the charge a few years back with the relaunch of its Texan bar and more recently Cadbury momentarily brought Wispa back to life.

You can see why. As marketing ploys go, it's flawless - it requires little effort and almost guarantees column inches in the tabloids.

But it's also a sad reflection on the state of NPD in the chocolate confectionery category where most 'innovation' is either new packaging or just a variation on a theme.

Lyndon Johnson once said: "We can learn lessons from the past, but we cannot live in it." He wasn't talking about chocolate bars, of course, but confectionery manufacturers should take heed nevertheless.