The number of prisoner complaints soared to a record high last year, a report has revealed.
Most of the complaints came from Dumfries Prison
A total of 460 grievances were filed by inmates, the largest number in the 12-year history of the Scottish Prison Complaints Commission (SPCC).
The report showed there were 70 more complaints than in the previous year.
The biggest number of grievances came from Dumfries Prison. Officials said increased awareness of the complaints procedure had to led a rise.
At Dumfries Prison, five individuals logged most of the 172 complaints.
During the past year the 178-bed jail has seen a large increase in serious sexual offenders, who are segregated from the general prison population for their own safety.
Last year Dumfries came under fire from inspectors for "failing to move with the times" and operating old-fashioned equipment and procedures.
The prisoners' most common complaints this time involved the overall prison regime, as well as facilities such as exercise, education and prison transfers.
The next most complained-about prison was HMP Peterhead in Aberdeenshire, which also has a high sex offender population and witnessed 98 complaints.
Grievance levels at the country's 13 other establishments were much lower, with Polmont Young Offenders' Institution registering just one complaint.
A total of 363 of the 460 complaints lodged came under the SPCC's remit.
Most common issues related to orderly room proceedings - held when a prisoner is charged with a breach of the prison rules - as well as matters about staff, prison regimes and health and safety.
Other instances included one inmate whose clothing went missing during a prison transfer, another who did not want to share a cell and one who complained when he was accused of being "disrespectful to an officer".
Despite the record number of grievances, SPCC commissioner Vaughan Barrett said he was encouraged that 127 complaints had been successfully resolved this year, more than double the number dealt with the year before.
For the first time no formal recommendations needed to be filed to the Scottish Prison Service as a result of the complaints.
Some complaints were about prison regimes
Mr Barrett said: "The challenges faced by our staff in considering, investigating and responding timeously to such a high volume of complaints were significant.
"I am extremely pleased to report that we maintained our standard of completing our investigations and issuing final responses within six to eight weeks in 70% of cases.
"This is not only conducive to prison staff and prisoners' well-being but it is likely to have a positive influence on a prisoner's disposition when he is released and will hopefully contribute to a reduction in reoffending."
Mr Barrett urged MSPs to give the SPCC a formal remit under an Act of Parliament.
A spokesman for the Scottish Prison Service attributed the increase in complaints to an increase in awareness of complaints procedures.
He said the high number of complaints at Dumfries could be due to the fact that sex offenders were now housed there.
Commenting on the request for the commission to be established under an Act of Parliament, a spokesman for the Scottish Executive said: "The commissioner is aware that this matter is being looked at as part of a wider review of scrutiny bodies."