The site www.cheestrings.co.uk/worldtourgame enables kids to race vehicles of their own design, as well as gain access to other users' designs (which are given a special number plate).
But when kids (or is that big kids?) entered the "garage" section of the website and tapped in the number plate code HHR 255, they were treated to a race in a car shaped like a giant phallus, complete with genital foliage.
The initial conclusion was that a disgruntled Fallon employee was responsible, but it transpires the dick debacle was the work of thecockrule.com - a site dedicated to one man's mission to draw a penis on any website with a builtin user-generated drawing function. Sadly, the offending car has since been removed from the site.