A prison where 10 inmates have committed suicide in the past three years has been criticised in what a watchdog calls a "depressing" report.
Ms Owers said prisoners at risk had been poorly supported
The Chief Inspector of Prisons makes 166 recommendations for improvement at 760-bed Woodhill, in Milton Keynes.
Anne Owers said at-risk prisoners were poorly supported, and anti-bullying measures had not been brought in.
The Prison Service said Woodhill was not performing strongly, but some areas such as healthcare had been praised.
Ms Owers criticises the jail for failing to deal with bullying.
Seven out of 10 prisoners reported being victimised in the previous month, Ms Owers found.
Concern was raised over the prison's anti-bullying strategy
Describing one case, she said: "Night staff on the first night unit had recorded in the staff observation book that a prisoner had said he was going to kill his 'pad mate', tie him up and put him under the bed.
"Staff also recorded that the same prisoner continued to abuse his intended victim verbally.
"The intended victim had been moved... but the information had not been passed to the security department and the perpetrator had not been dealt with under the anti-bullying scheme or prisoner disciplinary rules.
"Anti-bullying procedures were not implemented properly - indeed many staff were unaware of them."
There were just five Samaritans-trained "listeners" in the whole jail and no posters were displayed advertising their availability, inspectors found.
Ms Owers said staff in charge of youths held in the prison had not been trained or vetted to work with them.
She said many recommendations made in 2002 over the self-harm of prisoners had not been brought in.
The report says Woodhill has had 10 self-inflicted deaths in the last three years, nine within the first month of custody and five within the first week.
Ms Owers said: "Prisoners who were at risk of self-harm or suicide were poorly supported and managed."
The report criticises the lack of Listeners - prisoners trained by the Samaritans counselling service - available to prisoners in their early days at the prison.
Ms Owers said: "Overall, this is a depressing report.
"Woodhill was not providing a sufficiently safe and positive environment for its prisoners. Moreover, this finding appeared to come as a surprise to many staff and middle managers."
Prisons Handbook editor Mark Leech said the Prison Service needed to take action on the "damning report".
Phil Wheatley, director general of the Prison Service, said: "Whilst the prison is clearly not performing strongly, Anne Owers does recognise in her report that there are areas in which the prison is performing well, including healthcare and detoxification.
"The new Governor will vigorously implement an improvement programme which prioritises safety and resettlement."