Allen attended 13 schools, including Prince Charles's junior alma mater, Hill House School, Millfield, Bedales School and was expelled from several of them for drinking and smoking. When Allen was eleven, former University of Victoria music student Rachel Santesso overheard Allen singing "Wonderwall" by Oasis in the school's playground; impressed, Santesso, who later became an award-winning soprano and composer, called Allen into her office the next day and started giving her lunchtime singing lessons. This led to Allen singing "Baby Mine" from Disney's "Dumbo" at a school concert.