Some fast-food companies also cannibalised their own profits by trying to give customers better value.

The firm insists this has neither cannibalised sales of its other chips as much as feared nor put pressure on its lofty margins, since Atom costs less to make.

In the chocolate-bar market in Britain, for instance, the decline in Kit Kat's share was arrested by the launch of a new, more chunky bar, which undoubtedly cannibalised the market for the original.