Imagine you are accused of a serious crime. It goes to court. You’re tried in front of a jury of your peers. The verdict is in. Not Proven. What happens next? Is it the same as Not Guilty? And if not, in what way is it different? Did the jury believe you? Or do they still have their doubts? And how will the verdict be seen by your friends and family, your employer, the wider world: what will they think of it all? What does the Not Proven verdict actually mean?

This, essentially, is how the not proven verdict actually works in Scotland and has always worked. Questions are asked but never answered. Not Proven is widely used but never explained. No one ever tells a jury what the definition might be nor do they tell them what the difference is between Not Proven and Not Guilty (if there is one). Indeed, judges in Scotland are specifically instructed not to explain the verdict to juries and there’s a good reason for that: nobody knows. Which begs an important question for Scotland’s justice system: if lawyers can’t explain why there should be three verdicts in Scotland, then why do still have them?

That question is one that’s often come up over the years, and it’s regularly debated in the legal community, but it’s been given a new significance in the last few days now that Nicola Sturgeon, First Minister and former lawyer, has intervened in the debate. Ms Sturgeon said that for a long time she had been a supporter of the three-verdict system – guilty, not guilty, not proven – based on the idea that it was one of the foundations of Scottish criminal law. But she said this week that she’d now changed her mind. “It is something that it is time to look at,” she said.

The reason for her change of mind, says Ms Sturgeon, is the use of not proven verdicts in rape cases. “The conviction rate for rape and sexual assault is shamefully low,” she said, “and I think there is mounting evidence and increasingly strong arguments that the not proven verdict is part of that.” And, in a rare example of agreement between the two, the First Minister seems to have support from the leader of the Scottish Conservatives: Douglas Ross says his party is committed to abolishing not proven.

What’s been particularly driving the argument in recent months has been a campaign by Rape Crisis Scotland and a woman known as Miss M. In 2018 Miss M sued Stephen Coxen, who was accused of raping her and tried in 2015. The criminal trial ended in a not proven verdict, but the sheriff in the later civil case ruled Coxen had raped Miss M and was entitled to compensation. Miss M and Rape Crisis Scotland have since argued that the case demonstrates the not proven verdict should be abolished.

Their argument has several strands. First, they make the same point the First Minister made: the conviction rate for rape is low and Not Proven is used disproportionately in such cases. They also say not proven has the same impact as not guilty and can be just as distressing for the complainant and, finally, they argue that there is evidence some juries are prone to believing “rape myths” – that a person will always fight back, for example, or that they will always report the rape immediately – and that those who believe such myths may go for Not Proven as an easy way out.

Recent research by the Scottish Government appears to support some of the arguments made by Rape Crisis. The study suggested jurors have inconsistent views on the meaning of not proven and how it differed from not guilty and that removing the not proven verdict might incline more jurors towards a guilty verdict in finely balanced trials. The Justice Secretary Humza Yousaf said after the research was published at the end of 2019 that he would engage in discussions with lawyers and the public about whether Scotland should move to a two-verdict system.

But most lawyers are sceptical and, according to a survey carried out by the Open University last month, most are opposed to the removal of the Not Proven verdict, although it’s not quite as simple as that. Criminal silk Thomas Ross QC tells me he used to be a big defender of the three-verdict system on the basis that if juries found it helpful, why change it? But what changed it for him was his conclusion that there is a stigma around Not Proven. “Lawyers can protest as much as they want but there are an awful lot of people out there who are not lawyers who think it’s a tainted verdict,” he says. “If there are two acquittal verdicts and you get the second one, not proven, rather than not guilty, then people will inevitably think, well, that must mean something.”

The question is what to do about it, and that may depend on whether the Scottish Government accepts the arguments made by Rape Crisis. On their first argument on the conviction rate for rape, the figures are clear: convictions in 2018-19 showed a slight increase in the conviction rate for rape and attempted rape, from 43 per cent to 47 per cent, but it remained the lowest compared to other crimes. The figures for 2016/17 also show that the not proven verdict is more likely in rape cases: nearly 30 per cent compared to 17 per cent for all crimes and offences.

But the critical question is whether there is necessarily a connection between the two – conviction rates and not proven - and Thomas Ross is doubtful. “Nicola Sturgeon has a bizarre way of describing it, saying the conviction rate in rape trials is unacceptable and the not proven verdict is something to do with that, but in the first place, why is the conviction rate unacceptable because juries should only convict if the case is proved beyond reasonable doubt – in all the cases where the accused has been acquitted, the jury has not been convinced beyond reasonable doubt. The other thing is they don’t have the not proven verdict in England and there are even fewer convictions down there than they here.”

Mr Ross says there are also logical reasons why the not proven verdict is used more often in rape cases. “It’s obvious why it’s quite a frequent verdict in rape cases because in a robbery case, you might have 12 sources of evidence, including eye witnesses; you never have that in a rape case. It’s two people in a room and they both have their say and then there may be medical evidence which is often close to neutral. So it’s natural that the jury are going to say ‘we’re going to go for not proven’.

“I also think that if we removed the not proven verdict tomorrow, juries would acquit. It’s a hard thing for a citizen to say ‘I’m going to make a decision that sends that person to jail for seven years’ and I do think they take the presumption of innocence seriously and they need to be sure about it. In a week from now, they need to be able to look at themselves in the mirror and think I did the right thing. Cases where there’s a good believable complainer and a good believable accused and not much in the way of medical evidence, they would still end in an acquittal.”

Mr Ross is also sceptical about the argument that not proven should be abolished because it can be just as distressing for a complainant as not guilty. “Douglas Ross said we’re fed up with victims being disappointed because it’s a not proven verdict and we’re fed up with these victims not getting justice but I said to him: what reaction do you expect to get when you go and tell the victims that it’s a not guilty verdict because the not proven has been abolished? Naturally victims are going to want somebody convicted so any verdict that wasn’t a guilty verdict is going to disappoint them. And Nicola sturgeon makes exactly the same error.”

The final argument that’s used to challenge the use of not proven in rape cases is the idea that some juries may be prone to believing “rape myths” and may go for Not Proven as an easy way out but the problem here is that we just don’t know whether that is true or not. The Scottish Government research on juries used “mock juries”, but can volunteers watching mock cases really replicate the reality of sitting on a jury with the fate of another human being in your hands? The value of such research was questioned in a study by University College London published at the end of last year, which concluded that the claims that jurors are prone to rape myths is based on anecdotal evidence or mock juries rather than empirical evidence.

The central problem is we actually don’t know what juries think, or how they really behave, because there has never been any contemporaneous research conducted in Scottish courts with real jurors. They may be prone to believing rape myths. We don’t know. They may also be uncertain what Not Proven actually means. Again, we don’t know. In the absence of any explanation from judges – even if an explanation were possible – juries are effectively left to decide for themselves how to differentiate between Not Proven and Not Guilty.

If there is any consensus about what should be done, it’s that we need to find out what’s really going on. Thomas Ross says the research on juries that does exist is inadequate and flawed and we need proper research conducted by teams that are in court every day and speaking to jurors who have just conducted a real case. Perhaps then we will really find out what they think about Not Proven and what effect it is having on their deliberations and their decisions.

There is also a consensus building that Scotland should move to a two-verdict system – the only question is which two verdicts. The Open University study found that lawyers’ first preference was for a two-verdict system based on Proven and Not Proven and this would certainly be Thomas Ross’s choice based, he says, on the logic of how court cases work.

“The question for the jury is always: has the Crown succeeded in proving its case beyond reasonable doubt,” he says. “The jury would say yes or no, proven or not proven, and the judge would translate that into guilty or not guilty. It’s all about truth. Given the whole trial has been about proof, it seems sensible to me to then use the word proof when it comes to their job. It also takes the burden off them a bit – saying someone is guilty is quite a dramatic thing.”

But perhaps we should leave the final word on the subject to Sir Gerald Gordon, the great barrister and sheriff and author of seminal works on Scottish criminal law. He said that either there is a difference between not guilty and not proven, in which case the jury deserves to know what the difference is, or there is no difference in which case there is justification for having two verdicts. That is a perfect summary of the problem of Not Proven. It is also impossible to disagree with. And it’s probably why Scotland’s three-verdict system is going to have to change.