A prisoner takes their own life every three days as the number of suicides in jails reaches "epidemic proportions", campaigners have warned.
The Howard League for Penal Reform said it has been notified of 102 people dying by suicide behind bars this year.
With five weeks left until the end of the year, the death toll is already the highest in a calendar year since current recording practices began in 1978, according to the charity.
The revelation will spark fresh questions about the state of prisons in England and Wales following claims the system is "in meltdown".
The Howard League released the figures on suicide as it published a joint report alongside Centre for Mental Health, another charity.
It said the rise in prison suicides has coincided with cuts to prison staffing and budgets, along with an increase in the number of people in prison, resulting in overcrowding.
There has been a rise in violence while prisoners are spending hours locked in their cells each day, the paper added.
Howard League chief executive Frances Crook said: "The number of people dying by suicide in prison has reached epidemic proportions.
"No one should be so desperate while in the care of the state that they take their own life and yet, every three days a family is told that a loved one has died behind bars.
"Cutting staff and prison budgets while allowing the number of people behind bars to grow unchecked has created a toxic mix of violence, death and human misery."
The report called for the "incentives and privileges" scheme in prisons to be scrapped, saying it was having a "detrimental impact" on inmates' wellbeing.
Under the regime, some prisoners have limits placed on family contact, physical activity and access to money and possessions, the report said.
Incidents of self-harm and apparent suicides have surged against a backdrop of grave warnings about safety in prisons.
A number of self-inflicted deaths in recent years have been linked to new psychoactive drugs - previously referred to as "legal highs".
The prison population, which currently stands at about 85,000, has come under the spotlight in recent days.
Former justice secretary Michael Gove warned that too many people are being sent to prison, while the Lord Chief Justice suggested more criminals could be punished without being jailed.
Earlier this month, thousands of officers stopped work in protest amid soaring levels of violence and self-harm in prisons - forcing ministers to seek an emergency injunction to order them back to work.
It came after a string of high-profile incidents including the escape of two inmates, who were later recaptured.
Justice Secretary Liz Truss has unveiled a wide-ranging blueprint for prison reform, including an additional 2,500 officers and measures to stop drones dropping drugs into jails and to block the illegal use of mobile phones.
A Government spokeswoman said: "Mental health in custody is taken extremely seriously and there are a range of measures already in place to help support prisoners.
"Providing the right intervention and treatment is vital to improving the outcomes for people who are suffering and all prisons have established procedures in place to identify, manage and support people with mental health issues.
"But we recognise that more can be done. That is why have invested in specialist mental health training for prison officers, allocated more funding for prison safety and have launched a suicide and self-harm reduction project to address the increase in self-inflicted deaths and self-harm in our prisons."