The figures for 2019/20, published by the Scottish Government, showed while there was a 4 per cent decrease in criminal convictions overall, for rape and attempted rape the rate doubled.
There was a slight drop of 2 per cent in the number of convictions for all sexual crimes – down from 1,224 in 2018/19 to 1,204 – but total convictions for rape and attempted rape fell from 142 in 2018/19 to 130.
Chief executive of Rape Crisis Scotland, Sandy Brindley, said the conviction rate underlined the need for all political parties to follow through on their manifesto commitments to scrap the not proven verdict.
“In 2019/20 there were 2,343 rapes and attempted rapes reported to the police, but only 300 prosecutions and just 130 convictions,” she said.
“It is clear that the Scottish criminal justice system is failing the vast majority of people in Scotland who have been raped.
"Rape already had the lowest conviction rate of any crime type. To see it fall further – to only 43 per cent of cases which make it to court – is alarming.
"The not proven verdict, which is used disproportionately in rape cases, was used in 44 per cent of acquittals. Political parties, including the SNP, need to follow through on their commitments made during the election campaign to remove this confusing and redundant third verdict.”
Ms Brindley added: “It is clear that action is needed to improve justice following rape. In March the review group chaired by Lady Dorrian, the Lord Justice Clerk, released a comprehensive and bold report with key recommendations about how justice responses to sexual crime in Scotland could be improved.
"Acting on these recommendations must be a priority for the new government. It is the least that rape survivors deserve.”
Meanwhile the figures on domestic abuse convictions were welcomed by Scottish Women’s Aid, who said they were proof the “gold standard” legislation was working.
According to the statistics, there was a “notable rise” of 21 per cent for convictions of non-sexual crimes of violence, from 1,772 in 2018/19 to 2,142 in 2019/20, which was due, in part, to the introduction of the new crime of domestic abuse under the Domestic Abuse (Scotland) Act 2018.
There were 206 convictions under the legislation, from a total of 246 people brought to court, giving a conviction rate of 84 per cent.
There were also 8,120 convictions for crimes where the statutory domestic abuse aggravator was proven in the same year – a 5 per cent increase from 7,751 in 2018/19.
Marsha Scott, chief executive of Scottish Women's Aid, said: "These statistics offer some interesting glimpses into the operations of our criminal justice system and raise some critical questions for those of us working to end domestic abuse and protect the children and women who are living with it in their lives every day.
"Although it is very early data, our new domestic abuse law shows signs of living up to its global ‘gold standard’ label. A conviction rate of 84 per cent is impressive, and we wish to applaud the efforts of our colleagues in COPFS [Crown Office and Procurator Fiscal Service] and Police Scotland.”
But she added: "We do, however, have concerns and questions.
"Nearly two-thirds of disposals for domestic abuse cases were community sentences. We need clearer information about these sentences.
"Are children and women safer? How many of these cases involve repeat offences, and to what extent do community orders reflect the supposed seriousness with which Scotland takes domestic abuse?
"And we note that 38 of the convicted offenders also had a statutory aggravation for domestic abuse in relation to a child. We welcome use of the aggravation, but wish we had data about how many cases overall included children, and we hope that data will be collected and published in future reports.”
Overall the total number of people proceeded against in Scottish courts fell by 4 per cent to 85,726 in the year to 2019/20, continuing a ten-year downward trend.
The average length of custodial sentences for all crimes, excluding life sentences, was almost a year – 9 per cent longer than in 2018/19 – and 22 per cent of people convicted were given a community sentence.
Scottish Conservative justice spokesman Liam Kerr said the figures were evidence of the SNP’s “soft-touch” justice attitude and a failure to put victims first.
He said the SNP’s decision to “effectively scrap prison sentences of less than a year” had resulted in almost half of violent criminals avoiding jail, despite violent crime rising between 2018/19 and 2019/20.
"By effectively scrapping prison sentences of less than a year, the SNP are letting more and more violent criminals off the hook,” he said.
"The Scottish Conservatives warned this would be the case when this policy was forced through, but SNP ministers wouldn’t listen.
“Now we see almost half of violent criminals are avoiding jail due to the SNP’s obsession with soft-touch justice. They continue to let victims down again and again despite violent crime being on the increase.
"All too often they pander to the interests of dangerous criminals rather than standing up to victims.”
A Scottish Government spokesperson said: “Decisions about sentencing in any given case are for the independent courts and a court can impose a sentence of 12 months or less as it is a presumption, not a ban on short sentences. Evidence shows re-offending rates are lower for those serving their sentences in the community.
“More generally, these figures show that when people commit crimes, law enforcement agencies can and do take action and over the long term, we have seen a significant reduction of police recorded non-sexual violent crime of 34 per cent between 2006/07 and 2019/20.
“We are determined to do even more to prevent and reduce the harm caused by violence and have invested over £23 million in violence prevention programmes since 2008.”
Scotland's Domestic Abuse and Forced Marriage Helpline can be contacted on 0800 027 1234 and the helpline is open 24 hours.