I am standing on a grey slate star, embedded in the pavement of Edinburgh's Royal Mile. Today, this spot looks like any other bit of Heritage Britain, only with extra shortcake. Five hundred years ago, if legends are to be believed, it was very different: this was the site where Britain's first and greatest mass murderer was imprisoned; a man so evil his entire family was burned alive, alongside the psychopathic paterfamilias.

This notorious fellow was Alexander 'Sawney' Bean. Gazing down at the sidewalk star, I think back to where I first encountered him.

I was ten years old, and thumbing through my Christmas present – a copy of the 1973 Guinness Book of Records.