I have not provided specific guidance to the CPS on this issue, and neither has the Attorney-General.
As the Crown Prosecution Service is now responsible for advising the police on cases for possible prosecution and deciding whether to charge in all but the most minor of cases, cases involving false rape allegations will be referred to prosecutors for a charging decision. Potential charges are wasting police time and perverting the course of justice.
All cases must be reviewed in accordance with the code for Crown Prosecutors. Application of the code means that a case is prosecuted when there is sufficient evidence for a realistic prospect of conviction and that the prosecution is in the public interest.
Specific guidance on public justice offences is published jointly by the CPS and the Association of Chief Police Officers. The guidance provides that it is likely that a charge of perverting the course of justice will be appropriate when the making of a false allegation wrongfully exposes another person to the risk of arrest, imprisonment pending trial, and possible wrongful conviction and sentence.