Overcrowding at Barlinnie has hit an all-time high and is approaching almost double its design capacity.
The design capacity for the Glasgow prison is for 1018 inmates, but the latest total was 1718, the highest in its 126-year history.
It has risen from 1600 since July and accounts for a large proportion of the Scottish record total of 8013, which was recorded on August 25.
The statistic is revealed today after Justice Secretary Kenny MacAskill yesterday urged critics of reform proposals to get behind plans to toughen community sentencing.
The design capacity for all Scotland's 15 prisons is 6625. They now have 8075 inmates.
The total number of people within the system, including home detention, is now 8428 - up from 7483 a year ago.
A spokesman for the Scottish Prison Service confirmed the record figures last night and added: "We are experiencing high numbers all through the estate.
"Prison population has increased year on year for the past while and that is why the government commissioned the Scottish Prisons Commissions report."
Yesterday Mr MacAskill faced down opponents of wide-ranging changes to the justice system as set out in the recent report by former First Minister Henry McLeish, the commission's chairman.
Mr MacAskill broadly welcomed that report, which called for low-level offenders to be "worked hard" in the community.
The independent Scottish Prisons Commission report also recommended a target to cut the number of inmates from a projected peak, if unchecked, of 8700 to 5000 within a decade.
Mr MacAskill said a sentencing council will create clear guidance to ensure the Scottish justice system remains "respected".
He said the Custodial Sentences and Weapons (Scotland) Act 2007 will improve sentence management.
The Justice Secretary also praised summary justice reforms which made on-the-spot fines possible.
Of the latest prison levels, Labour's Shadow Justice Minister Paul Martin said: "These figures show that Barlinnie is bursting at the seams and the SNP is failing on crime.
"Ministers must provide reassurance that serious offenders will not be released back on to the streets without serving their full sentence."
