The Scottish Parliament is to approve major reforms to the country’s legal system, including the removal of the not proven verdict.

The government’s Victims, Witnesses and Justice Reform (Scotland) Bill also proposes raising the bar for a guilty verdict in criminal trials and paves the way for the creation of a special sexual offences court.

The bill has already been controversial, with ministers dropping plans for juryless rape trials following criticism from lawyers and judges.

MSPs agreed several amendments to the bill following a six-hour debate at Holyrood, with a final vote to follow on Wednesday.

The SNP does not have a majority at Holyrood, but the bill is expected to pass after the Scottish Greens said they would back it.

The headline proposal of the reforms is the removal of the not proven verdict – a legal idiosyncrasy that can be traced back to the 17th Century.

In Scots law criminal cases it is one of three possible verdicts, along with guilty and not guilty.

There is no set definition of a not proven verdict, or how it is different from not guilty. Indeed the result of a not proven verdict is exactly the same as a not guilty verdict – the accused is acquitted and is innocent in the eyes of the law.

Some argue that it provides extra protection to the accused by reducing the risk of wrongful conviction. But critics say that it is confusing for juries and the public, can stigmatise an accused person by appearing not to clear them, and fails to provide closure for victims.

A study published in 2019 found removing the not proven verdict might incline more jurors towards a guilty verdict in finely balanced trials. It also highlighted inconsistent views on the meaning of not proven and how it differed from not guilty.

Justice Secretary Angela Constance, who is steering the bill through parliament, described not proven as a “widely misunderstood” verdict that “traumatises” victims and leaves a “lingering stigma on the accused”.

Another major change in the bill is the proposal to introduce a two-thirds majority for a guilty verdict. Currently, a simple majority of eight jurors out of 15 is sufficient. The new rules would increase that to 10 out of 15 jurors.

Raising the bar for guilty verdicts is intended to allay the concerns of some defence lawyers who fear the the abolition of the not proven verdict could make it harder to help their clients avoid a conviction.

Prosecutors fear the two-thirds rule will make it harder to secure a conviction.

Originally, the government wanted to cut the size of juries in criminal cases from 15 to 12, but this idea was later shelved.

Another key pillar of the bill is a proposal to create a sexual offences court.

Ministers say this would prevent victims from being caught up in judicial backlogs and improve their experience in the justice system by introducing “trauma-informed” training for judges and legal staff.

Constance told MSPs: “The hierarchy and tradition woven through our system is not delivering for victims. We need systemic reform which will enable us to build a new culture, processes, procedures, from the ground up.”

However, Scottish Labour MSP Pauline McNeill said that ministers had not provided “concrete” evidence that the sexual offences court would cut delays is the system.

The bill would also pave the way for the government to establish a victims and witnesses commissioner. The independent office would be in charge of ensuring standards of care for victims and would be answerable to parliament.

The government has not set a timescale for scrapping the not proven verdict or introducing a two-thirds majority for guilty verdicts. Before the changes are introduced judges and court staff would need to undergo training.

It could take significantly longer to set up a sexual offences court and a victims commissioner.

The bill also includes provisions for:

• an automatic lifelong right to anonymity for victims of sexual offences and certain other offences
• automatic independent legal representation to complainers in sexual offence cases when defence lawyers want to use evidence relating to their sexual history or character
• extending rules that restrict what can be said in court about a complainer’s sexual history
• a requirement for the parole board to consider if a murderer has refused to reveal the location of their victim’s remains when considering if they should be freed from jail. The measure has been named Suzanne’s Law, after Edinburgh woman Suzanne Pilley.
• changes to make it easier for vulnerable witnesses to give evidence in civil cases, for example by appearing from video link or from behind a screen
• reforms to the Victim Notification Scheme – which gives victims the right to receive information about the release of an offender from jail – to ensure it works in a “more trauma-informed and person-centred way”

There was broad agreement in parliament about scrapping the not proven verdict, but opposition parties called for further justice reforms.

MSPs also raised concerns about trying to push through such a wide range of reforms in one bill and being given limited time to debate complex amendments.

Constance has said the reforms will improve protections for victims and witnesses while protecting the rights of the accused.

But Scottish Conservatives leader Russell Findlay described the bill as a “massive missed opportunity”.

More than 160 amendments were lodged at stage three of the bill’s journey through parliament. Several were passed with the government’s support.

These included Scottish Conservative leader Findlay’s proposal for victims in solemn cases – which deal with the most serious crimes – to be informed if a plea deal has been struck between prosecutors and defence lawyers, if they request that information.

However, ministers did not back another of Findlay’s amendments calling for the government to set up a grooming gangs inquiry.

MSPs also backed amendments that, once enacted, would:

• ensure courts always consider a non-harassment order to protect victims in sexual offence, stalking and intimate images cases
• create a victims charter, setting out victims’ rights and what to expect in the justice system
• give victims the right to be told about a decision not to prosecute
• make permanent a trial scheme giving victims of rape and serious sexual assault free access to court transcripts
• widen a scheme that allows victims of some offences to make a statement about the impact of the crime to help inform sentencing decisions
• seek reassurances over measures to improve the experiences of victims and witnesses, particularly women
• ensure the parole board takes into account the safety and security of victims and their families when considering whether prisoners should be released. The proposal is named after Ayrshire teenager Michelle Stewart, who was murdered by her ex-boyfriend
• compel ministers to review how courts manage domestic abuse cases where there are connected proceedings

Announcing her party’s support for the bill, Scottish Greens justice spokeswoman Maggie Chapman said scrapping not proven was necessary “for a clearer, more humane and modern justice system”.

Liberal Democrat MSP Jamie Greene, who tabled the amendments on the victims charter and the right of victims to be informed about prosecution decisions, said: “I am confident that this bill can now make an important difference for the victims of crime and their families.”

He added: “I encourage all parties in Holyrood to not play political games at the final hurdle and support this bill.”

A final vote on the amended bill is scheduled for about 16:00 on Wednesday.

Once a bill is passed by MSPs it has to be rubber-stamped by the King before it can become an act of law.

The push for reform comes as Lord Advocate Dorothy Bain, Scotland’s top law officer, makes clear her desire to improve the justice system for victims of sexual offences.

Most rape cases reported to police do not lead to prosecutions. To address this, ministers proposed a pilot scheme that would have allowed trials for serious sexual offences to be held without a jury and decided by a single judge.

However, this measure was dropped from the justice reforms due to a lack of cross-party support.

Last year, after being asked by the lord advocate to consider the issue, judges overturned an 87-year-old rule on corroboration in rape and sexual abuse cases.

One year on, the Scottish legal system is heading for an even bigger shake-up.