Scottish Conservative leader Douglas Ross has vowed to scrap the not proven verdict in criminal trials which has subsisted since the 19th century.

There have been several attempts to remove the third option during the 20th and 21st centuries. As recently as 2016 the Scottish Parliament overwhelmingly voted against a call to abolish the verdict – which legally has the same effect as ‘not guilty’. Most of the members of the Scottish Parliament’s justice committee at the time backed its removal, with the convener then Christine Grahame MSP saying that the Criminal Verdicts Bill ‘shone a light on the ambiguities of the not proven verdict’.

The burden of proof in a criminal matter is to prove the accused is guilty ‘beyond reasonable doubt’. Where that cannot be proved there are two options – not guilty or not proven.

High Court of Justiciary where the most serious criminal trials are conducted. Photo: Martin P. McAdam

Those who push for reform say that a not proven verdict is equal to an acquittal where the court does not have sufficient evidence to convict, but is not sure enough to hand down a ‘not guilty’ verdict. But those who wish it retained as an option are mindful of wrongful convictions if there were only two options.

According to recent statistics one third of jury verdicts hand down a not proven decision, and it is used more in the more serious cases.

At the party’s conference in Perth, Douglas Ross will say the controversial verdict “serves no useful purpose in a modern justice system”.

His pledge will be a key justice policy in the Scottish Conservative manifesto for next year’s Holyrood election.

It has according to the Scottish Conservatives, been welcomed by campaigners including Joe Duffy whose daughter Amanda, 19, was murdered in 1992. The case against her alleged killer Francis Auld was found ‘not proven’.

Also backing the announcement is Miss M, who successfully sued her alleged rapist after he received a not proven verdict in 2015.

Scottish Conservative leader Douglas Ross said: “We are fully committed to scrapping not proven. Many people who have suffered the horror of serious crime have had their pain compounded by this damaging and confusing verdict.

“Having examined this issue in detail, and having listened to victims, it clearly serves no useful purpose in a modern justice system.

“The time is right for Scotland to give jurors the clear choice between guilty and not guilty.”

Responding to the Scottish Conservative pledge, Joe Duffy said: “Myself and my family are delighted the Scottish Conservatives are including a proposed change to the three-verdict system in their manifesto and advocating to end the contentious not proven verdict.

“The return of a not proven verdict exacerbates the trauma and loss for victims and their families. It is misunderstood, unnecessary and out of date.

“We sincerely hope there will be cross-party support in the Scottish Parliament for this proposal for the benefit of everyone affected by the criminal justice system.”

Miss M said: “I began the End Not Proven campaign in collaboration with Rape Crisis Scotland two years ago this week.

“I am pleased to see political parties recognising this issue. I have met with each party and expressed my concerns to the First Minister and hope to see continued support.

“We have the evidence, and Scotland’s survivors and their families have spoken out. It’s time to end the use of not proven – a misunderstood acquittal verdict which causes untold damage”.

The Scottish Conservatives conference is taking place on Friday and Saturday. Douglas Ross will speak to conference at 3pm on Saturday.