Prisoners forced to hide in their cells for months at a time through fear of being attacked by violent inmates were branded "scaredy cats" by guards, inspectors visiting an out-of-control prison in Staffordshire have said.

HMP Featherstone was found to have suffered a "shocking" decline in safety over the past three years as rampant drug use fuelled a rise in violence behind bars.

A number of prisoners were said to have become so afraid of being attacked they would seldom leave their cells, spending "day after day" hiding behind locked doors.

They also told inspectors that even in their locked rooms they were not safe, with their attackers spitting, shouting and urinating at them though the gaps of their cell doors.

"Most of these prisoners felt at risk of violence because of debts and had asked to stay locked behind their door for their own protection," the inspection report, published on Tuesday (27 February), said.

"These 'self-isolators' told us about the abuse they suffered, describing people shouting through, spitting at and urinating under the cell door.

"They could not access showers, exercise, food or work without fear of repercussion.

"Most were locked up for 24 hours a day. Some officers showed concern, while others referred to them as 'scaredy cats' and described their predicament as 'self-inflicted'."

It added: "Many remained isolated for weeks, and some for months, at a time and we had concerns about their well-being."

HMP Featherstone has become just the latest prison to be criticised by inspectors as jails across England and Wales suffer a record number of assaults behind bars amidst staff cuts and rampant drug abuse.

The chief inspector of prisons, Peter Clarke, said there had been a "shocking worsening in standards" for the prison's 640 male inmates since the last inspection in 2013.

Inspectors found during their visit to the category C training facility in October and November last year that some 37% of inmates surveyed felt unsafe – more than double the number in 2013, when the figure stood at 15%.

The facility had become awash with drugs, they added, and suffered from "poor industrial relations, staff shortages and some significant prisoner unrest".

Clarke said: "Given the well-known destabilising influence which a high level of drug availability has in prisons, with the associated debt and bullying feeding a cycle of violence, perhaps we should not be surprised at the serious decline in the safety of the men at Featherstone.

Spike in assaults caused by new drug

"If the prison is to once again become a safe and decent place which can fulfil its role as a training and resettlement prison, there needs to be dynamic, visible leadership which gets to grips with the serious issues we have identified."

One in five prisoners surveyed said they had developed a drug addiction since entering the jail, while almost two-thirds said it was easy to get hold of illegal substances.

This included new psychoactive drugs said by the Ministry of Justice to have caused a country-wide spike in the number of assaults behind bars.

Living conditions were also found to be in a poor state, with "filthy" showers often broken and unfit for use.

"Many cells were dirty, poorly ventilated, covered in graffiti and in need of decoration. Prisoners could not always access basic essentials such as an adequate supply of clean prison clothing, sheets or towels," the report added.

While noting the impact understaffing had on the prison regime, Clarke also criticised the prison's senior leadership team for failures.

He accused them of not having "sufficient knowledge or oversight of some key areas, including use of force, the unregulated segregation of self-isolators and the lack of outdoor exercise for prisoners".

While only 16 of 68 recommendations made following the 2013 inspection had since been implemented, inspectors said they were, however, pleased to find the quality of teaching, learning and assessment in education and vocational training was "good".

Michael Spurr, Chief Executive of the National Offender Management Service, said in response to the inspection report: "The deterioration in performance at Featherstone isn't acceptable but reflects the real pressures which the system has faced over the last few years. The Government have set out a clear plan for reform in the Prison and Courts Bill laid before Parliament last week, including investing over £100m to provide 2,500 additional prison staff.

"This will make a difference and with these additional resources and committed focused leadership I'm confident that the Governor and management team at Featherstone can turn things round and achieve the improvements required."