An inquiry has been launched into the death of an inmate at HMP Nottingham three weeks after the prisons watchdog called for the Government to intervene at the "fundamentally unsafe" jail.
Darren Capewell was pronounced dead on Wednesday and the Ministry of Justice has said an independent investigation will be carried out.
The 37-year-old's death comes after chief inspector of prisons Peter Clarke used the urgent notification system for the first time to put Justice Secretary David Gauke on notice that immediate action was needed.
Inspectors visited HMP Nottingham on January 8, the third inspection in little over three years, and found levels of self-harm had risen "very significantly", as eight prisoners were believed to have killed themselves.
Mr Clarke sent a letter to the Justice Secretary saying the prison had been found fundamentally unsafe for the third inspection in a row, which led him to issue the urgent notification.
In response to Mr Clarke's letter, Mr Gauke said: "The chief inspector has rightly identified the very difficult challenges and circumstances staff at HMP Nottingham are facing, and it is clear they need support to help deliver a safer establishment for staff and offenders.
"We have already provided more experienced staff to the prison and boosted the number of prison officers by more than 100.
"I will be looking closely at the issues faced by the prison and will publish an action plan within 28 days which will urgently drive improvement required."
A Prison Service spokeswoman said: "HMP Nottingham prisoner Darren Capewell died in custody on Wednesday.
"As with all deaths in custody, there will be an independent investigation by the prisons and probation ombudsman.
"Our sincere condolences are with the family of Mr Capewell at this difficult time."