Roy Kerr, aka the Freelance Hellraiser, is one of the creators of the UK bootleg scene.
He gained fame with a mash-up in 2001 called "A Stroke of Genius", which combined an instrumental edit of The Strokes' track "Hard To Explain" with Christina Aguilera's pop hit "Genie in a Bottle". James Hyman who, along with Eddy Temple-Morris, championed mash-ups and the song in particular on the Xfm show The Remix, described it as "so musical. It was the result of a sick mind, and a trainspotter's mind, and a musician's mind." Although originally greeted by a cease and desist order by RCA (the label which both Aguilera and The Strokes are signed to), The Freelance Hellraiser went on to remix Aguilera's single "Fighter", as well as tracks for Placebo and ex-Verve frontman Richard Ashcroft. "A Stroke Of Genuis" was later dubbed as "the song that defines the decade" by The Guardian
In 2004, he was commissioned by Paul McCartney to remix some lesser-known McCartney tracks as preshow entertainment for his tour of that year. Those tracks, and several more, were released under the name Twin Freaks.