As he published his annual report, Prisons and Probation Ombudsman Nigel Newcomen said the increase reflected the level of mental-ill health in prisons and “a rising toll of despair” among some prisoners.
Mr Newcomen said it suggested the need for the Prison Service to review its suicide and self-harm procedures.
Some 90 inmates took their own lives in the year 2013/14, up from 55 the previous year.
Mr Newcomen said: “It has been suggested that prison staff are now so stretched, and the degree of need among some prisoners so high, that they may no longer be able to provide adequate care and support for some vulnerable prisoners.
“The evidence for this remains anecdotal and every day prison staff do save many prisoners from themselves – an achievement which goes largely unreported and without which the tragic number of suicides would be even higher.
“Nevertheless, the prison system is undeniably facing enormous challenges.
“It is nearly a decade since the Prison Service introduced its current suicide and self-harm procedures and, given the examples of poor implementation described in this annual report and the worrying increase in suicides, I believe it is time to review and refresh these arrangements.”
Juliet Lyon, director of the Prison Reform Trust, said: “If the tragic and rapid rise in the number of self-inflicted deaths in custody does not wake ministers up to the damage drastic cuts and rushed policy decisions are doing to the prison service and the people in its care, it is hard to know what will.
“It’s time to reserve prison for the most serious and violent offenders and to ensure that, wherever possible, people who are mentally ill are diverted into the care and treatment they so urgently need.”
Prisons Minister Andrew Selous said: “Reducing the number of self-inflicted deaths in custody is a key priority.”