Diabolical Liberty by G. Llewellyn Barker
Teenager Thomas Scrimshaw is trapped in a boring office job until a chance encounter plunges him into a world of nightmares and fear. Framed for a murder he didn't commit, Tom is forced to take on clueless cops, corrupt courts and a spiteful troll who looks like Ozzy Osbourne. While he's hunted by the authorities, his friends and his strange benefactor Theo Jinnee race to the rescue. But are all of them really on his side? Diabolical Liberty is part crime thriller, part comic fantasy with more levels than The Shard.