The POA is meeting Irish Prison Service (IPS) boss Caron McCaffrey on Wednesday, when it will repeat its call for a joint management-prison officer task force to deal with the crisis.

The latest figures show there are now 500 more people in prison than the system can take, at its maximum.

More than half of these 500 inmates are in bunk beds crammed into cells and almost another half are sleeping on mattresses on cell floors.

The prisons worst affected are the two female jails — the newly-refurbished Limerick Female Prison and Dóchas in the Mountjoy complex — followed by Limerick’s male prison and Mountjoy.

Prison numbers breached the 5,000 mark for the first time ever on Thursday, June 20, with 5,002 inmates in cells that have capacity for 4,514 people.

That record was beaten twice last week, with 5,007 prisoners on Wednesday and 5,015 on Thursday.

A breakdown from Thursday shows:

• Limerick Female Prison has 72 inmates in spaces for 56 people (129% over capacity) with a further 24 prisoners on temporary release (TR);
• Limerick Male Prison has 349 inmates in spaces for 286 people (122% over capacity), with 58 prisoners on TR;
• Dóchas has 181 prisoners, in spaces for 146 people (124% over), with 69 on TR;
• Mountjoy has 885 inmates in spaces for 755 people (117% over), with 154 prisoners on TR.

The POA told the Irish Examiner that industrial relations have “totally collapsed”.

Its deputy general secretary Gabriel Keaveny blamed the crisis on the “lack of planning” by senior officials in the Department of Justice and the IPS.

“There’s inevitably going to be trouble,” Mr Keaveny said. “We warned everyone, we told the minister, that we cannot see how we are going to get through the summer. There will be huge conflict in cells.”

He added: “I am 33 years in the prison service and I have never seen so many cells doubled up — hundreds of bunk beds have been shoved into cells in Mountjoy, Cork, and the Midlands.

“You take Cork Prison, one of the newest prisons — every single cell, bar one or two, has been doubled up and you still have over 50 prisoners sleeping on the floor [on mattresses]. In Mountjoy, where you have so many protection prisoners and a number of feuding organised crime groups, it’s a recipe for disaster.”

Mr Keaveny said overcrowding meant greater competition among prisoners for telephone calls, for the tuck shop, and access to workshops and gyms, leading to “heightened tensions”.

There is also serious concern regarding Cloverhill Remand Prison, where, according to figures from January, there are 216 prisoners in cells for three people and 172 prisoners in cells for four people — all of whom have to share a cell toilet.

“If you have a guy sleeping on a mattress in a cell with three other people, sharing a toilet, with little air, and it’s warm, the officer could be dealing with a very volatile situation when he opens the cell door in the morning,” said one source.

In a statement, the Department of Justice said: “The Irish Prison Service continues to engage with the Department of Justice to progress plans to bring new spaces for over 1,100 people on stream between 2024 and 2030, with short-term projects progressing, which are expected to deliver accommodation for over 170 people this year.”

The IPS said it “must accept all prisoners committed by the courts”.

It said a “multi-agency Prison Overcrowding Response Group” has identified a number of proposals to address overcrowding.