Bailey became a Member of the Royal College of Psychiatrists (MRCPsych) in 1976 and was elected a Fellow of the Royal College of Psychiatrists (FRCPsych) in 1996. Since 1983, she has been a consultant child and adolescent forensic psychiatrist at the Greater Manchester West Mental Health NHS Foundation Trust. In 1993, she appeared as an expert witness in the James Bulger murder trial. She concluded that one of Bulger's killers, Jon Venables, knew the difference between right and wrong: information that led to them being convicted of murder.