Liam McArthur

Barlinnie was operating at 139 per cent of its capacity. It housed on average 1,371 prisoners in the first half of December 2018, despite its design capacity being set at 987. A further eight prisons reported occupancy rates of 100 per cent or higher.

At the start of 2018, just five prisons had average populations at or breaching their design capacity.

Mr McArthur said: “These new figures show that our prisons are bursting at the seams with the majority now full or overcrowded. People are being packed in like sardines.

“Those working in prisons have warned that the population surge is putting services at risk and jeopardising progress.

“Prison capacities are set for a reason. Staff need to work in a safe environment. Overcrowding makes it harder for them to work with individuals and help rehabilitate them.”

He added: “Scottish Liberal Democrats demand better. Many people in prison are on short-term sentences, despite all the evidence showing these make their lives more chaotic and are less effective at rehabilitating people than robust community-based sentences. That is why the Scottish government now must get on and introduce a presumption against short-term sentences of less than 12 months.

“Ministers need to urgently ease the pressure on our prison system and change the way we deal with less serious offenders to make our communities safer.”