Incidents of self-injury by prisoners have "rocketed" over the past five years, figures show.
In 2003, there were 16,393 incidents of self injury in prison, compared to 22,459 incidents last year.
Rates among women prisoners rose even further, with a 48% rise in recorded incidents between the same period.
In Styal prison, self-injury rates among female prisoners rose from 376 to 1,324 in the past five years.
The Howard League for Penal Reform said the figures reflected only registered incidents, and that a significant number were going unreported.
Frances Crook, director of the Howard League, called the rise in self-injury a "national scandal". She added: “This shocking rise is far above what might be expected as we lock up ever increasing numbers of men, women and children whose mental health problems and addictions will never be properly treated within our flooded and failing jails."
A public inquiry into the treatment of a girl who self-harmed in prison will begin later this year.
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