Woodhill prison suicide rate an 'unacceptable toll'
Nine suicides at a prison since 2012 have been described as an "unacceptable toll" in a report.
A report on HMP Woodhill in Milton Keynes said levels of violence, including assaults on staff, were "much higher" than compared to most prisons.
Transgender prisoner Joanne Latham was found hanged in her cell in December.
Inspectors said tackling violence and suicides had to be the prison's "main priority". Similar concerns were raised in 2014.
Figures show there were 89 apparent self-inflicted deaths across the prison estate in England and Wales last year.
HMP Woodhill, a Category A prison, opened in 1992 and can hold 819 inmates.
The report found there had been progress in providing work, training and education, there was support given to prisoners at risk of suicide and self-harm, and drug availability was lower than elsewhere.
Deputy chief inspector of prisons Martin Lomas, said: "HMP Woodhill is an improving prison and its very good purposeful activity and good rehabilitation services are better than we have seen recently in many other local prisons.
"Good outcomes in these areas help to create a sense of purpose and hope and reduce frustration and tension.
"Despite this, levels of violence are a significant concern and the number of self-inflicted deaths in recent years has been unacceptably high.
"The main priority of the prison must be to tackle these two areas."
Michael Spurr, chief executive of the National Offender Management Service, said tackling increased levels of violence and preventing suicides was the top priority for the Prison Service as a whole.
"Tragically, as recent incidents at Woodhill have demonstrated, the challenge is considerable - but we will use the recommendations in this report to further develop and improve our approach," he added.