A plan to temporarily release prisoners from jail in an effort to control the spread of coronavirus has been suspended after six inmates were mistakenly let out of prison.
The Prison Service said it was aware of a “small number” of low-risk offenders who were freed too early.
The inmates were wrongly let out of two open category D prisons in Gloucestershire and Derbyshire, Leyhill and Sudbury, along with one inmate from the Isis category C prison and young offenders institute in south-east London.
The government’s early release scheme, designed to avoid thousands of inmates becoming infected, was paused on Thursday and is due to resume next week.
Up to 4,000 prisoners in England and Wales, who often have to share a cell, were to be temporarily released from jail in an effort to try to control the spread of coronavirus.
Launching the scheme at the start of the month, the Ministry of Justice said the selected low-risk offenders would be electronically tagged and temporarily released on licence in stages, although they could be recalled at the first sign of concern.
The justice secretary, Robert Buckland, said the move was part of the national plan to protect the NHS and save lives.
The Prison Service blamed human error and said processes would be changed.
A spokesman said: “We are aware of a small number of low-risk offenders who were released from prison under the temporary early release scheme following an administrative error. The men were released too early but were otherwise eligible under the scheme, and returned compliantly to prison when asked to do so.
“We have strengthened the administrative processes around the scheme to make sure this does not happen again.”
The news comes after prison charities launched legal action against the justice secretary claiming measures so far taken to address coronavirus behind bars are unlawful because they will have a “manifestly insufficient impact”.
Lawyers acting for the Howard League for Penal Reform and the Prison Reform Trust have written to Buckland with details of a proposed application for judicial review, should urgent action not be taken to address their concerns.
Campaign group the Prisoners’ Advice Service has also threatened legal action against the government unless vulnerable and elderly prisoners are immediately released to protect them from contracting Covid-19.
Coronavirus cases have been confirmed in half of the prisons in England and Wales.
A total of 255 prisoners had tested positive for Covid-19 in 62 jails as of 5pm on Thursday, the MoJ said, and 13 had died.
A total of 138 prison staff have also contracted the virus in 49 prisons, as well as seven prisoner escort and custody services staff.