She never had a Birmingham accent in the first place. She's middle class, from a well off family and went to a private school. I was a big fan of hers when I was a kid/teen, but the "overcoming prejudice in my journey up from the streets" routine was always fake. She played at being a punk rebel because suburbia bored her. Having said that, her talent was genuine, and she was successful enough in her day to deserve a star on Broad Street. Lesser successes than her seem to have been given one.