To become a qualified forensic psychologist you need to complete: 1  a British Psychological Society (BPS)-accredited degree in psychology, leading to Graduate Basis for Chartered Membership (GBC). 2  a Health and Care Professions Council (HCPC)-approved programme of training leading to registration as a forensic psychologist.o do a BPS-accredited degree you will usually need five GCSEs (A-C), plus three A levels. Check with course providers for exact entry requirements. If you are a graduate in a subject other than psychology you may be able to become eligible for GBC by completing an accredited conversion course.