An investigation has been launched after the death of an inmate at one of the region's biggest jails.
The prisoner at HMP Dovegate, in Marchington, was pronounced dead on Friday afternoon, December 22.
Serco, which runs the prison, confirmed the man’s death the following morning, but has not yet released details of his age or name.
A post-mortem examination will now be carried out to establish why he died before a report is prepared for the coroner ahead of an inquest being opened.
It is understood prison staff had tried to save the man but their attempts were unsuccessful.
In a statement, John Hewitson, Serco director at HMP Dovegate, said: "Sadly despite the best efforts of our staff, a prisoner died on Friday afternoon.
"As with any death at a prison, there will be a coroner’s inquest in due course."
Conservative MP Andrew Griffiths, whose constituency covers Uttoxeter, including the prison, today called for a "full and thorough" investigation into the sudden death.
He said: "Any death in custody is an extremely serious matter and I trust that the authorities will conduct a full and thorough investigation to find out what caused this tragic event to happen."
A spokesman for the Howard League for Penal Reform, a charity which campaigns for improvements to conditions inside prisons, said: "Every death in custody is a tragedy.
"Whenever a prisoner dies it is particularly important that an investigation is carried out in a timely manner and we trust that this will be the case here."
The Ministry of Justice confirmed it was aware of the death but declined to comment further.
HMP Dovegate currently has around 850 inmates. At its last inspection in the summer, the prison was criticised for its high levels of violence, self-harm and drug abuse.
However, the facility was praised for its programmes to help offenders quit substance abuse, good living conditions, and for the respect shown by staff.
Bosses at the prison insisted they were acting on the recommendations following the publication of the report in October.