In response to strawberry's writeup concerning a discontinued "candy bar" (or as us Brits say, "Chocolate Bar"), the Marathon was also the name of an item of confectionery sold in the UK made by Mars, Incorporated and renamed in 1993. Unlike the (presumably?) US product by the same name to which strawberry refers, this product is sold worldwide as the ubiquitous Snickers.
Much like Opal Fruits being renamed to Starburst, Oil of Ulay swapping a vowel for Olay and Jif becoming Cif, we in the UK have become used to familiar product names being rebranded to suit international marketing purposes.