Addressing the union’s annual conference in Kilkenny, acting president Peter Redmond said the prison population stood at a record 5,909 on March 24, compared with capacity for 4,736 – a shortfall of 1,173 spaces.

“This, combined with the myriad well-established issues resulting as a direct consequence of overcrowding, is a national scandal,” he said.

Mr Redmond said assaults on prison officers rose by 23 per cent between 2024 and last year, adding that overcrowding increased the availability of drugs, weapons and phones and “allows the bully and the gangs to thrive and ensures that the vulnerable prisoner becomes even more vulnerable”.

He noted that while inmate numbers have doubled over the past 26 years, only one new prison – the Midlands Prison – has been built. It currently holds 1,128 prisoners despite a capacity of 891, with 160 inmates sleeping on cell floors.

“This overcrowding issue was first raised by the Prison Officers’ Association some 50 years ago but successive governments have failed us and the prisoners we are supposedly rehabilitating,” he said.

Mr Redmond also highlighted a shortage of mental health support, saying that 2,425 prisoners – about 40 per cent of those in custody earlier this year – were awaiting psychological services. “This is a mental health crisis within our prisons,” he said.

He criticised plans to build 30 single-occupancy modular units at a cost of about €15m, arguing the expenditure was unjustified while prisons such as Mountjoy remained significantly over capacity.

“Seventy additional bed spaces have been created since [Justice Minister Jim O’Callaghan] was appointed. However, an additional 460 people have been imprisoned during this period,” he said.