The prisons watchdog has raised concerns about safety and overcrowding at Durham jail.
Inspectors said it was “unacceptable” that most inmates at HMP Durham had to eat their meals in their cells by an unscreened shared toilet.
The prison, which dates back to the early 19th century, holds just under 1,000 male inmates in aged and overcrowded accommodation, HM Inspectorate of Prisons found.
Most cells designed for one prisoner were occupied by two.
"They were cramped, and some were dirty and in need of redecoration," the inspection report said.
"There were many inappropriate pictures on walls and graffiti was widespread.
"Most cells only contained one chair and no lockable cupboards."
Four inmates had taken their own lives since the jail was last inspected in December 2013, while HMIP was informed of a further death the week after its visit in October.
In a survey, just under half of prisoners reported illicit drugs were readily available in the establishment.
Chief Inspector of Prisons Peter Clarke described the report as "disappointing", saying it was "striking how little had changed since our last inspection".
He said: "The prison had many strengths, not least a strong local identity and generally friendly staff, but the culture was not as constructive or purposeful as it should have been."
The findings are the latest in a catalogue of critical reports to emerge as jails across England and Wales attempt to tackle high levels of violence and self-harm.
Michael Spurr, chief executive of the National Offender Management Service, said: "The illicit supply of psychoactive drugs has undermined safety in Durham and tackling this, with the support of the police, is a priority for the governor.
"As HMI Prisons say, assaults have fallen since the last inspection and robust arrangements are in place to keep the public safe, but there is more to do."
Mr Spurr said additional staff are being recruited at Durham and expressed confidence that its performance will significantly improve.