A Detective Constable from Greater Manchester Police has been stabbed during an incident at HMP Frankland.
The officer suffered a single stab wound to the chest during the incident at approximately 11am this morning.
The officer suffered critical injuries and was taken to hospital by ambulance, but following treatment his condition is currently described as stable.
His family has been made aware and are being supported by police colleagues.
Detectives from Durham Constabulary are now investigating the incident, which occurred during an interview with a remand prisoner.
A man in his 60s has been detained and will be interviewed in due course.
Detective Chief Inspector Chris Smiles, who is leading the Durham Constabulary investigation, said: “First and foremost, our thoughts are with our colleague, who suffered appalling injuries while simply doing his job. Thankfully, his condition is no longer critical and we wish him a full and speedy recovery.
“We are liaising with the victim and his family and our investigation is ongoing.”
