A backing track some would consider as 'rock' or 'acoustic' if naive, but is widely known as 'indie', with a rap or hiphop singer or rapper, known as 'grime'.
Although you may think that this type of music would appeal to both 'chavs', and 'emo/scene' people, it tends to be liked by another breed of people, 'indie kids see indie
The word comes from the equation
grime + Indie = Grindie
Jamie T, Arctic Monkeys, Lily Allen, The streets, many more are examples of grindie music