A woman makes a rape allegation against a man, and then later retracts it.
Should she be prosecuted for perverting the course of justice? Behind that one question hides a matrix of others. Was she telling the truth? Was she bullied into withdrawing the allegation? Is there a history of abuse? Was it a malicious claim against an innocent man?
The Crown Prosecution Service is running a public consultation on this issue.
Responses to the consultation will inform guidance for CPS prosecutors which will outline the factors they need to consider before deciding whether or not to bring a prosecution over the retraction.
That guidance will aim to protect individuals who retract truthful allegations of rape or domestic violence because they are frightened, but make it more likely that those who make malicious false allegations are prosecuted.
These are complex cases and it is crucial that we get them right. Rape and domestic violence are devastating forms of abuse and victims should have confidence that their cases will be treated sensitively and robustly by the criminal justice system.
The role of the CPS is vital in that.
The CPS has faced legitimate questions recently over the handling of some rape and domestic violence cases.
In December last year I announced the first steps in a series of changes which I hope will trigger improvements in the handling of rape cases.
These included: strengthening the quality of communications with complainants; improving the way these cases are monitored; and pledging that the budget cuts we are facing cannot be allowed to affect the quality of rape prosecutions.
Earlier this month, I spoke to an audience of prosecutors and representatives from women’s charities about domestic violence.
I acknowledged that while much progress has been made in prosecuting offenders in recent years, police and prosecutors must still do more to tackle it.
The statistics are startling: nearly one million women are abused every year; two are killed every week by partners or ex-partners; and women experience an average of 35 incidents of domestic violence before reporting the abuse to the police.
So when, perhaps finally, a victim gathers the courage to tell the police what happened they should not do so in fear that they risk prosecution themselves.
One of the key reasons for issuing this interim guidance was to ensure that victims of rape and domestic violence have the confidence to report abuse, safe in the knowledge that they will only be prosecuted for perverting the course of justice if their original allegation is false, and not where they later feel unable to support a prosecution and withdraw.
This guidance asks prosecutors to look carefully at particular evidential and public interest considerations before making their decision.
Among those factors for determining whether there is sufficient evidence for a realistic prospect of conviction, the interim guidance asks that prosecutors should consider whether the CPS can prove an allegation was untrue.
If there is any doubt about that then a charge of perverting the course of justice cannot be brought.
Prosecutors are also asked to be aware that victims of domestic violence may sometimes retract truthful allegations as a result of pressure or fear of violence.
In such cases there is a risk that a complainant may admit to an offence simply to bring the original prosecution to an end.
Public interest factors, including whether a false complaint was motivated by malice and whether someone was convicted following an allegation that evidence now suggests was false, would make a prosecution for perverting the court of justice more likely.
Likewise, there are public interest factors which would make a prosecution less likely.
They include that the original allegation appears not to have been motivated by malice, and that the person retracting the allegation has been threatened or pressurised into doing so by the alleged attacker, their family or someone else.
I encourage all readers with expertise or an interest in this area to respond before the consultation closing date of 6 May.
You can read all the factors in the interim guidance at the CPS site.
Keir Starmer QC is director of public prosecutions