Ever since Lord Carloway recommended the abolition of corroboration - the need for two separate sources to support crucial evidence in a case - a great many lawyers have voiced grave doubts about the move.

One of the most compelling arguments put forward in favour of abolishing corroboration has been that it is an impediment to justice in certain cases, particularly rape, which has a woeful conviction rate in Scotland. Such cases often come down to one person's word against another's, so the need for a separate source of evidence besides the testimony of the victim has been blamed for stopping cases coming to trial.

The future of corroboration was cast in doubt following the Cadder judgment in 2010, which ruled suspects could no longer be questioned by police without a lawyer. It was feared this would make rape conviction even less likely since, previously, suspects might admit to police during interview that they had had sex with the complainant while denying rape, and their statement could then be used as corroboration that sex had taken place. Post-Cadder, on the advice of their lawyers, suspects would be more likely to say nothing, making it harder to meet the requirement for corroboration on that point.

Do away with corroboration, so the argument went, and this impediment to rape trials would be removed.

Would that translate into more rape convictions, however? Perhaps not. Today, the Faculty of Advocates warns it could in fact make conviction less likely, since there is a risk police officers will focus less in their investigations on finding corroborative evidence, thereby weakening the case that ultimately goes before the jury.

The crux of the faculty's argument is that getting to trial is only the first step. The way things stand, many sexual offences cases fall even where there is corroborative evidence; remove the need for it and it could make it tougher still to convince a jury that the accused is guilty.

The other side of this argument is one put forward by the Lord Advocate Frank Mulholland, among others, that many cases are currently failing to proceed at all because of the corroboration requirement.

So where does this leave the broader debate on this reform? Lord Carloway has stressed the importance of focusing on the quality rather than the quantity of evidence, a principle which has to be in the interests of justice.

The doubts and objections of lawyers must not be dismissed as professional pride or inertia, however. The Faculty of Advocates and Glasgow Bar Association have raised a serious question about the potential unintended consequences of abolition.

If it does go ahead, it will be essential that it proceeds hand in hand with other reforms, including increasing the jury majority required to return a verdict.

Meanwhile, it would be deeply worrying if police let up in their efforts to uncover supporting evidence in rape cases simply because of this reform. It is the responsibility of police, prosecutors and, indeed, ministers to ensure this does not happen.