The course of justice starts when:  EWCA Crim 1033 it was held that where the prosecution case is that a false allegation has been made, all that is required is that the person making the false allegation intended that it should be taken seriously by the police.
It is not necessary to prove that she/he intended that anyone should actually be arrested.
If a wrongful conviction is believed to have occurred because of the perjured evidence, a prosecution should follow, unless there are exceptional circumstances.
If the witness has lied to protect his or her own interests rather than with an intent to pervert the course of justice, a prosecution may be unnecessary.
Regard should be had to the case of (2002) TLR 29/5/02, which suggests the use of offences other than perverting the course of justice when other individuals are not exposed to risk.
Note that extended time limits apply to some summary only motoring offences and the principal offence can be prosecuted beyond the 6 months time limit.
The offence of perverting the course of justice is sometimes referred to as "attempting to pervert the course of justice".
It does not matter whether or not the acts result in a perversion of the course of justice: the offence is committed when acts tending and intended to pervert a course of justice are done. The offence of perverting the course of justice overlaps with a number of other statutory offences.
Although there may be public interest factors against prosecution in a particular case, prosecutions for public justice offences should usually go ahead and those factors should be put to the court for consideration when sentence is being passed.
It is likely that perverting the course of justice will be the appropriate charge when: Due to their sensitivity, and to ensure a consistent approach, all cases involving an allegation of rape in which consideration is given to prosecuting the complainant for perverting the course of justice must be referred to the Director of Public Prosecutions.
All cases referred to the CPS by the police, including those which are not thought to pass the Full Code Test, must be sent with an MG3 form including an analysis of the evidence and any legal issues submitted.
The words "attempting to" should not appear in the charge. Before preferring such a charge, consideration must be given to the possible alternatives referred to in this Charging Standard and, where appropriate, any of the following offences: Perverting the course of justice covers a wide range of conduct.
It is charged contrary to common law, not the Criminal Attempts Act 1981: 92 Cr. A charge of perverting the course of justice should, however be reserved for serious cases of interference with the administration of justice.The purpose of charging standards is to make sure that the most appropriate charge is selected, in the light of the facts, which can be proved, at the earliest possible opportunity.