A report has found levels of serious violence at Chelmsford Prison have fallen, but warned the jail still has a "significant drugs problem."
Peter Clarke from Chief Inspector of Prisons also said the care of vulnerable prisoners was improving following an inspection in April.
Mr Clarke found that serious violent incidents had been reduced by more than 50% at the prison and living conditions had got better.
However, a failure to tackle the amount of illegal drugs being smuggled into the prison "risked undermining other progress."
Mr Clarke also highlighted the fact that the number of suicide deaths "remained worrying", but said progress had been made in improving the quality of care for prisoners who were deemed to be at risk of self-harm.
He did warn though that the planned increase in the prison's population could result in the return of the overcrowding seen in 2018.
“Last year, I clearly noted my confidence in the prison’s capacity for change and improvement, and this was well-founded," Mr Clarke said.
"The governor continued to set a clear vision for the prison and had retained the support of those around her.
"We have identified good or reasonable progress in four key areas, and this report makes clear what needs to be done to make advances in the remaining weak areas.
"While additional regional and national resources had been used to good effect, the lack of more sophisticated drug detection equipment was indefensible, and the easy availability of drugs continued to undermine other progress made.”
What does the report say the prison still needs to improve on?
The prison still needs to be equipped with more up-to-date drug detection equipment
The complaints process for prisoners still needs work
Time out of cell is still too limited
Most prisoners are still only getting 30 minutes of exercise a day
Concerns remain about some key weaknesses in offender management arrangements