Dickinson's singing varied notably in the 1990s in the recording of albums such as "No Prayer for the Dying", "Fear of the Dark" and his first solo work "Tattooed Millionaire", making use of a much more raspy and unpolished sound, befitting their stripped down style. Since returning to Iron Maiden in 1999, his singing style has returned to much like it was in the 1980s, though his voice has lowered with age. According to a report published in the "Daily Mirror", Dickinson has an estimated vocal range of 4.25 octaves. His voice led to the nickname "The Air Raid Siren", which "Billboard" states is "due to the ferocious power of his singing", although Dickinson claims it actually originated from a fan complaint.