In England and Wales, the principal formal sources of sentencing practice are legislation and prior judicial decisions. The authors analyze "Billam's internal logic, the kind of sentencing practice prescribed, and how the guideline is being applied. The "Billam" sentencing guideline judgment specifies aggravating factors in rape: additional violence, weapon used, repeated rape, careful planning, previous convictions, further sexual indignities or perversions, very old or very young victim, and serious mental or physical effect on the victim. Mitigating factors specified are a guilty plea, victim behaved in a manner designed to lead the defendant to believe she would consent, and the defendant's previous good character. Irrelevant factors are imprudent victim behavior, and the victim's previous sexual experience. To examine how the "Billam" decision has been applied in subsequent rape cases, cases were selected at random from those reported in Thomas's (1992) "Current Sentencing Practice." The authors conclude that in appealed rape cases the Court of Appeal apparently has scaled its sentence without reference to "Billam" scaling implications. 4 tables, 14 references, and a table of cases