A prison where inmates are allowed to wear their own clothes and have phones in their cells has been praised for "bucking the trend" of rising violence.
Chief Inspector of Prisons Peter Clarke also found the use of so-called legal highs at Category B HMP Altcourse in Liverpool had dropped "considerably".
He praised the "excellent staff culture" and said nearly all staff and inmate interactions were "positive".
But he did report that the jail's offender management programme was weak.
Altcourse, which housed 1,148 men at the time of November's inspection, reported a total of 157 assaults in the previous six months, compared with 210 during the corresponding period of 2014.
Inspectors said most cells in the G4S-run jail had televisions, kettles and phones "which prisoners appreciated".
Mr Clarke said: "Overall, Altcourse was in some key areas bucking the trend when compared to other local prisons.
"While it still faced significant challenges around safety, the downward trend in violence and anti-social behaviour was highly creditable."
He concluded Altcourse showed a local prison can provide "fundamentally decent treatment and conditions for prisoners, despite facing many of the same challenges as the rest of the prison service".
Altcourse director Steve Williams said: "Despite facing some significant challenges in recent months, including going smoke-free in September 2017, I am heartened to see inspectors reflect the determination and commitment to safety at Altcourse."
Mr Clarke expressed concerns, however, about the preparation of inmates for release due to a "significant backlog" in offender assessments by the National Probation Service "for the riskiest men in the population".
Altcourse, which opened in 1997, was the first privately designed, constructed, managed and financed prison in the UK.
It is situated in the Fazakerley district of Liverpool.