A prison branded inadequate two years ago remains “very poor”, with “many violent incidents” leaving staff and inmates injured, inspectors have said.
Privately-run HMP Doncaster suffered from a “lack of staff” and “ineffective initiatives” aimed at reducing violence, a report said.
The National Offender Management Service said many issues identified in 2014 remained unaddressed.
Serco said it was addressing the problems with a new management team.
HM Inspectorate of Prisons found there had been 365 assaults in the previous six months, with serious injuries to both staff and inmates recorded.
In 2015, a prisoner was knocked unconscious by a fellow inmate and later died.
Drugs ‘widely available’
Self-harm was “very high” and there were three self-inflicted deaths in the past 18 months.
Wing staff were described as “overwhelmed”, with drugs “widely available”.
The unannounced visit in October found many cells had missing windows and were in a very poor state of cleanliness.
HMP Doncaster is a category B prison with more than 900 inmates, and has been operated by Serco since 2003.
The report did however praise the “many good staff” at the site and said the prison’s quality of teaching was generally good.
Martin Lomas, deputy chief inspector of prisons, said: “Doncaster has been a more effective prison in the past and we saw some very good people during our inspection. However, this report describes a very poor prison.”
Serco said it had recently appointed a new management team, with the site a “very different prison to the one inspected”.
Julia Rogers, from the firm, said: “We are continuing to address the issues raised in this inspection and safety has improved, violence is gradually reducing and the house blocks have been refurbished.
“Doncaster has a history of having previously been an excellent prison and we are determined that it will be once more in the very near future.”