A mouse infestation, Fight Club culture, drug use, and discrimination against minority groups were just some of the issues raised in a report on life behind bars at a Rochester prison.

Inspectors found HMP Rochester, which houses around 650 male inmates, has made improvements since its last inspection in 2011 but there was still a lot of work to do.

Communal areas were found to be dirty with underwear discarded on the floor, food waste and litter in the sinks and evidence of a mouse infestation.

Older parts of the prison were in a "very poor condition" with some cells deemed unsuitable for occupation.

Cells had broken windows and faulty ventilation, with some inmates resorting to blocking gaps in windows and vents with paper to keep out draughts.

According to the report, bullying and fighting is rife on the wings. The number of fights and assaults has declined from an average of 20 a month in 2010 to 10 a month at the end of 2012, but this is still higher than in similar prisons.

The number of incidents of bullying was also high. There were 167 reports of bullying in six months and bullying was found to be a particular problem in the older wings.

The report found there was a spate of organised fights, labelled as "a Fight Club culture", in December last year, but following measures to stop such incidents no more had taken place.

A significant number of prisoners from minority groups expressed a negative view of their treatment and inspectors described the prison's approach to equality and diversity as "lacklustre".

Inspectors also found there was no support for gypsy, Romany, traveller or gay and bisexual prisoners.

They discovered the prison's approach to security had improved significantly since the last report, but the use of illicit drugs was still too high - with 10.6% of prisoners testing positive for drug use during random tests.

"Rochester is not an easy prison to run. It is a complicated and mixed institution where change feels ever present..." - Nick Hardwick, HM chief inspector of prisons

Levels of activity and time out of cells has improved, but inspectors found too many prisoners "on the wings during the working day doing nothing" and too many activities were considered menial or unchallenging.

Nick Hardwick, HM chief inspector of prisons, has made a number of recommendations including a new diversity and equality action plan, improving work and training sessions, proactive work to reduce fights and bullying and refurbishing the older accommodation.

He concluded: "Rochester is not an easy prison to run. It is a complicated and mixed institution where change feels ever present.

"The prison was heading in the right direction and managers seemed to be working to a clear vision and plan, although this had yet to translate fully into clear improvements in outcomes for prisoners."

Rochester Prison expanded in 2008, when four new accommodation units were built, doubling the capacity.

In 2011, it became a duel-purpose prison - catering for both young offenders and adult male category C offenders.

Michael Spurr, chief executive officer of the National Offender Management Service, said the prison has improved during a period of considerable change.

He added: "I am pleased that the chief inspector has recognised the progress being made at Rochester.

"The governor and his staff are building on this good work by addressing the concerns raised in the report, particularly tackling the level of violence."