Douglas Ross

At the party’s conference in Perth, he said the 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 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.

Mr 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, Mr 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 It is misunderstood, unnecessary and out of date.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”.