The report says 40 inmates took their lives in 1991 and 41 in 1992. So far this year, 23 have killed themselves.
'Howard League research shows that the over-use of custody kills. The majority of people sent to prison are poor, vulnerable and young, and are not able to cope with the bleakness of prison life,' the league's director, Frances Crook, said.
Almost half of those inmates who killed themselves last year were under 25, according to the report, Dying Inside. In the last five years, 43 people under the age of 21 have committed suicide in jail, it says.
The Howard League is urging the Government to stop sending 15-year- olds to jail, highlighting the deaths of three boys in this age group over the past three years.