Inmates blocked gaps under their cell doors with cardboard and towels to stave off a rat infestation at a failing prison put into special measures by a watchdog, a report has said.

Chief inspector of prisons Charlie Taylor said the smell of rat urine was “overpowering” in some areas of HMP Rochester in Kent.

A report published on Tuesday detailed the “squalid” and “decrepit” conditions, rising violence, self-harm and widespread drug use which prompted the watchdog to call on the justice secretary to make major improvements at the lower security jail, making it the first category C prison in England and Wales where a so-called urgent notification was issued.

The training and resettlement prison, designed to prepare reforming criminals for life outside jail when they are released, holds more than 700 men on the site of the UK’s first borstal – a youth detention facility – with some accommodation dating back to the late 19th century.

It is among nine prisons to have been issued with an urgent notification since November 2022, joining Bedford, Bristol, Exeter, Manchester, Wandsworth, Winchester and Woodhill jails, as well as Cookham Wood young offender institution.

Rochester prison had been condemned for closure a few years ago but stayed open in light of the overcrowding crisis in jails, Mr Taylor said after the latest inspection in August.

Despite this the underlying problems “have not gone away” and there had been a “shocking level of neglect” and a “decade of decline” at the prison which had “persistently underachieved” during five inspections since 2013.

Drug use was “endemic” and there were growing numbers of violent attacks on staff, according to the findings.

The report said the dilapidated jail was “fundamentally failing in its rehabilitative purpose as a category C training and resettlement prison” with some of the worst conditions inspectors had seen in recent years.

“Staff and prisoners told us that rats and mice regularly entered cells and offices on the older wings.

“Prisoners resorted to creating barriers from cardboard or towels to fill gaps under cell doors to keep vermin out,” the report said, adding: “The smell of rat urine in some areas was overpowering.

“Throughout the inspection both staff and prisoners complained about the infestation.

“Staff showed us where the rats had come in through ducting and around pipes.

“It was evident that mice were also commonplace, and on some wings nearly all prisoners put makeshift barriers beneath their cell doors to try to keep rodents out.”

Andrea Coomber, chief executive of the Howard League for Penal Reform, said: “This report into Rochester prison underlines the terrible situation that the current Government inherited on taking office. But it also underlines the fact that Government ministers can only use that as an excuse for so long.”

She welcomed recent efforts to tackle problems in prisons, but warned: “If we are still seeing inspection reports like this in a year’s time, then the Government will have only itself to blame.”

In September, prisons minister Lord Timpson insisted urgent improvements would take place to tackle drug problems and “dangerously high levels” of violence.

He said: “We are taking immediate action to improve conditions at HMP Rochester, offering additional support for our hard-working staff and addressing the drivers of violence.”

Security measures will be reviewed, more effort will be made to get prisoners into training and education, and cells are being refurbished, a Ministry of Justice spokeswoman said.