Prison staff are taking “unlawful” action by protesting over “unprecedented” violence and safety concerns in prisons, the Government has said.

Members of the POA, the trade union for prison staff, have been asked to demonstrate outside prisons in England and Wales from 7am “until instructed otherwise”.

It follows a damning report warning of a “dangerous lack of control” at HMP Bedford, their union said.

Standards across the prison estate have come under intense scrutiny in recent years amid a slew of highly critical reports and a deterioration in safety measures.

Prisons minister Rory Stewart said: “Prison officers do vital and important work and we urge them to return to their duty stations, in line with their obligations to the law and the prison service.

“It’s irresponsible for the POA to encourage their members to take this unlawful action. We are deploying our contingency plans but, by not turning up for work, these prison officers are putting their fellow staff and inmates at risk.”

The Ministry of Justice (MoJ) said it would be seeking an injunction to stop the action.

POA General Secretary Steve Gillan said the majority of prison officers would be outside prisons in car parks in protest against the “unprecedented decline in health and safety standards over past six years”.

He told the Press Association: “We are coming out in protest to bring attention, under health and safety legislation, to the Government, to the general public, about conditions in our prisons for both prisoners and my members, of the rise in violence, the rise in drugs, the self-harm and everything that goes with it.”

Mr Gillan went on: “Under legislation the Government and employer have a duty of care toward my members, and I’m fed up of hearing of my members receiving smashed eye sockets, broken arms, broken legs, broken jaws, being attacked, spat on, having excrement and urine thrown at them, and enough is enough now.

“We need ministers to start taking control of what’s going on.”

The POA, which said it has 20,000 members in England and Wales, said about 90% of prison staff were members of the union.

On Thursday, Chief Inspector of Prisons Peter Clarke raised the alarm over the potential for a “complete breakdown” in order and discipline at HMP Bedford.

Inmates have effectively taken control at the violent, overcrowded and vermin-infested jail, his report has warned.

Brian Cooper, POA branch chairman, was among some 50 officers picketing outside the prison, which he said was “unsafe every day”.

He said staff are on long-term sick leave with post-traumatic stress disorder (PTSD) and other mental health issues created by the violent and drug-fuelled conditions, which he blamed on cuts to the prison budget.

Those demonstrating have received a letter signed by governor Helen Clayton-Hoar ordering them to return to work and threatening disciplinary procedures and docked pay packets.

The HMP Bedford report is the fourth urgent notification the Government has issued since the scheme was introduced less than a year ago.

The process has also been triggered in relation to HMP Nottingham, HMP Exeter and HMP Birmingham.

In his annual report for 2017/18, Mr Clarke warned that staff and inmates have become “inured” to conditions unacceptable in 21st century Britain.

He highlighted how thousands of inmates are living in squalid and overcrowded cells, locked up for nearly 24 hours a day.

Official figures published in July revealed that assault and self-harm incidents were continuing to rise, both reaching new record highs.

Authorities are also faced with a major task to stem the flow of contraband.

In the 12 months to March, there were 13,119 incidents of finding drugs in prisons – a rise of nearly a quarter (23%) compared to the previous year.

In particular, new psychoactive substances such as Spice have been described as a “game-changer” for safety behind bars.

Discoveries of mobile phones and SIM cards are also on the rise, going up by 15% and 13% respectively in 2017/18.

Overcrowding remains a key issue, with the prison population almost doubling between 1993 and 2016.

The prison population is forecast to “steadily” rise by more than 3,000 over the next five years, according to Ministry of Justice analysis, reaching roughly 86,400 places in March 2023.

The MoJ said it doubled the prison sentence for anyone who assaults prison officers on Thursday.

It is also investing £40 million to improve the estate and tackle the drugs problem, with 3,500 new officers to help ease the burden.