More than 600 assaults have taken place in a Tayside prison in the last five years.
New figures show that between 2013 and 2017, bosses at HMP Perth recorded 612 violent incidents.
The prison — previously dubbed the most violent in Scotland — recorded more serious assaults than any other jail, with 12 between April 2016 and March 2017.
HMP Barlinnie, the largest prison in the country, only registered five serious assaults during that period.
Additionally, there were 69 attacks on prison staff during that time.
The figures, released via a freedom of information request, highlight a huge surge in violence between 2014 and 2016.
Overall, 129 assaults were reported in 2014/15, which rose to 178 incidents in 2015/16.
During that period, serious assaults rose to 13 from just seven the previous year.
HMP Perth saw the largest increase in attacks between 2014 and 2015, with at least one serious assault every four weeks.
Only four incidents were recorded at Castle Huntly in five years.
Scottish Conservative justice spokesman Liam Kerr MSP said he believed the figures merited “serious scrutiny”.
He added: “The prison’s assault record has been so bad in the last two years that it’s skewed Perth’s overall crime rates.
“We don’t want it to be known as Scotland’s most violent.
“The number of assaults against members of staff is concerning and deserves serious scrutiny.”
Mr Kerr added: “The year to 2016 was Perth’s worst in half a decade. Last year, the number of assaults went down slightly, which is good, but the reduction is marginal and still much higher than it should be.
“The safety of prisoners and prison staff is extremely important and I hope the Scottish Prison Service can provide a reason why the last two years have been so violent.
“Most of the prisoners at Perth will be patient for their release date.
“An environment in which they may not feel safe is not good for rehabilitation.”
The Scottish Prison Service has been asked to comment but had not responded at the time of going to press.