The number of people who took their own life while on supervision after leaving prison has increased sixfold since 2010 to a rate of one every two days, fresh analysis seen by the Guardian shows.

There were 153 self-inflicted deaths among those on post-custody supervision in 2018-19, compared with 24 in 2010-11, Ministry of Justice data analysed by the charity Inquest reveals, although this is partly down to improved recording.

The suicide rate among people leaving prison in 2018-19 was 212 per 100,000, while for people serving community orders and suspended sentence orders (who are under supervision but have not been jailed), the rate falls to 132 per 100,000, Inquest said. The rate for prisoners is about 83 per 100,000 and among the general population it is about 14 per 100,000.

A joint briefing paper by Inquest’s head of policy, Rebecca Roberts, and Jake Phillips of Sheffield Hallam University says all deaths of people on post-custody supervision should be investigated by an independent body such as the prisons and probation ombudsman.

In the paper’s foreword Inquest’s executive director, Deborah Coles, says: “The figures are deeply disturbing and require urgent scrutiny, due to the current lack of independent investigation into these deaths.

“Without this, we cannot fully understand what is happening or how it could be addressed. What is clear however is that people are being released into failing support systems, poverty, homelessness and an absence of services for mental health and addictions. This is state abandonment.”

In light of the sharp rise in the number of deaths, Her Majesty’s Prison and Probation Service and the National Probation Service have committed to performing an in-depth review of the deaths of people under post-sentence supervision. This will include working closely with the Office for National Statistics to improve the quality of the data and to inform the MoJ’s understanding. The review is due to be completed by March 2020.

However, it is understood that while probation staff help offenders find access to vital services including healthcare, housing and treatment for drug and alcohol problems, the MoJ does not expect them to have sole responsibility for caring for the people they are supervising.

The prisons ombudsman opened investigations into 334 deaths in 2018-19, 96% of which were of people in prison. The only deaths of people under probation supervision that were investigated by the ombudsman were those of 12 residents in probation approved premises, some of whom will have been on post-custody supervision, the paper said.