Number of prisoners freed by mistake hits highest level for six years
The number of prisoners mistakenly released has reached the highest level for six years.
Sixty-five convicted criminals or suspects were freed in error in 2015/16 - an increase of 16 compared with the previous year and the highest in any financial year since 2009/10, when there were 68.
It means inmates were let out because of blunders at a rate of more than one a week.
A prisoner is officially classed as having been released in error if they are wrongly discharged from an establishment or court when they should have remained in custody and when they had no intention to escape.
The Ministry of Justice said examples can include misplaced warrants for imprisonment or remand, recall notices not acted upon, sentence "miscalculation" or "discharging the wrong person on escort".
Figures obtained by the Press Association last year showed that individuals in custody for murder and other violent offences were among hundreds mistakenly released in a decade.
Lucy Hastings, of charity Victim Support, said victims will be "alarmed and frustrated" by the latest findings.
She added: "We know it can be distressing and worrying when offenders are released from custody - releases made in error can make this many times worse."
It came as a rash of official data sparked fresh concerns about safety in prisons in England and Wales.
Assaults on prison staff are at record levels, with 15 attacks every day. In the year to the end of March there were 5,423 assaults on officers - up 40% on the previous year. The tally included 646 serious incidents.
The overall assault count was up by almost a third to more than 22,000, while in the 12 months to the end of June there were 105 apparent self-inflicted deaths - up from 82.
Shadow prisons minister Jo Stevens said the figures "show the absolutely unacceptable state" of the prison system in England and Wales, adding: "Neither prison staff nor prisoners are safe.
"Fifteen assaults on prison staff every single day cannot continue. Prisoner suicides have increased and the number of people who've been accidentally released from prison is at a six-year high."
Mike Rolfe, national chairman of the Prison Officers' Association, said: " These damning statistics demonstrate that frontline prison staff are now three times more likely to be assaulted than in 2010."
Justice Secretary Liz Truss described the level of violence in prisons as "unacceptable".
She said : "I am clear that safety in prisons is fundamental to the proper functioning of our justice system and a vital part of our reform plans.
"There are a number of factors, including the availability of psychoactive substances in prisons, which must be tackled. It will take time to address these long-standing problems.
"I am determined to make sure our prisons are safe and places of rehabilitation."
It was also disclosed that:
:: As of the end of last month, 1,341 offenders freed on licence and then recalled to custody after breaching the conditions of their release were still at large, including 177 who were originally serving a sentence for violence and 42 sex offenders. The figures include some individuals believed to be dead or living abroad, the MoJ said;
:: The overall performance of six prisons was rated as being of "serious concern";
:: One in four adult or juvenile offenders committed a new offence within a year of being cautioned, convicted, or released from custody. The reoffending rate of 25.7% is a slight fall on the previous 12 months.
:: In 2015/16, 24.5% of prisoners were held in "crowded" conditions, a decrease of 1.0 percentage points from 2014/15.
On releases in error, a Prison Service spokeswoman said: "These incidents are extremely rare and the vast majority are returned to custody very quickly.
"But we are not complacent and thoroughly investigate each incident to see what lessons can be learned, as well as working closely with the police to recapture offenders at large as necessary."