A woman inmate has been found hanged in her cell at Durham Prison.
More than 100 women are held at Durham Prison
Police named the woman as 35-year-old Wendy Booth from York.
She was serving a life sentence for murder.
A post-mortem examination is due to be held on Friday.
A spokesman for Durham Police said Ms Booth died on Wednesday.
She was discovered in her cell, in which she was the sole occupant, by prison staff.
Attempts to revive her at the scene failed.
The police spokesman said there were no suspicious circumstances surrounding the incident.
In 2002, the Prison Reform Trust said more inmates took their own lives at Durham Prison, than at any other jail in the country - six suicide deaths were recorded at Durham last year.
Durham Prison, which is the UK's only high security jail for women, has been criticised for overcrowding.
In September, the regime at the prison was severely criticised, as a jury returned an open verdict into the death of one of four inmates who died in a nine-month period.
The jury at Durham Magistrates Court returned the verdict on the fifth day of an inquest into the death of 32-year-old Jamaican, Beverley Fowler.
She was found hanging in her cell in October 2002 - two days before she was due to be deported after completing a sentence for smuggling class A drugs into Britain.
During the hearing, the pressure group Inquest, criticised conditions at the prison's female unit, which houses more than 100 inmates.
The group claimed there were too many prisoners
for the staff to monitor closely.
The prison service has recently employed an expert solely to study suicides among women at the jail.
A Prison Service spokeswoman said: "We are overhauling the way the female population is managed so we can tailor prisoners` movements more appropriately to the needs of the women concerned.
"We do accept that suicides have risen over the past few years, and we are in the middle of a three-year strategy to reduce self-harm."