Some 37 offenders who were prosecuted using old harassment law have been released in error as part of the Government’s early release scheme.

The PA news agency understands some offenders, sentenced using old harassment law, were not flagged as being exempt from the temporary early release scheme, which Lord Chancellor Shabana Mahmood introduced to “avert disaster” amid a capacity crisis.

The Prime Minister’s spokesman said ministers introduced the early release scheme to head off “paralysis of the criminal justice system” and he echoed the Ministry of Justice’s official comment that public safety is the Government’s “first priority”.

Ms Mahmood cut temporarily the proportion of sentences which inmates must serve behind bars from 50% to 40% during the summer.

The Cabinet minister exempted some offenders from the scheme if their crimes were linked with stalking, controlling or coercive behaviours in an intimate or family relationship, non-fatal strangulation and suffocation, and breach of restraining order.

However, the technical glitch affected breach of a restraining order cases prosecuted using the Protection from Harassment Act 1997, after its replacement – the Sentencing Act – was passed in 2020.

Offenders prosecuted using the older legislation were not labelled as being ineligible for early release.

Among the 37 offenders mistakenly released, the ministry is working with the police to return five offenders to custody with the majority back in prison, and it has issued staff with guidance in an effort to block further incorrect releases.

“Public safety is our first priority,” the Ministry of Justice spokesman said.

“That is why we took decisive action to fix the broken prison system we inherited and keep the most dangerous offenders locked up. This included blocking the early release of domestic abuse offences such as stalking and controlling behaviour.

“We are working with the police to urgently return a very small number of offenders – who were charged incorrectly and sentenced under repealed legislation – to custody.

“The convictions remain valid with offenders monitored since their release and will soon be back behind bars.”

Prime Minister Sir Keir Starmer’s spokesman said: “Clearly public safety is always the Government’s first priority.

“When the Government came into office we were facing a paralysis of the criminal justice system and the Government had to take action.

“There were exemptions and safeguards put in place in relation to blocking the earlier release of offenders.

“We’re working with the police urgently to return the people that you refer to who were sentenced using outdated legislation. They’ve all been monitored since their release so they will be brought back into prison.”

Liberal Democrat justice spokesman Josh Babarinde described the mistake as “deeply shocking news” and called on the Government to develop a “plan to reduce reoffending and tackle the prison backlog without delay”.

He said: “The public deserves immediate action so that all those who were mistakenly released from prison are swiftly returned, and to prevent this from happening again.

“The Conservatives have neglected our criminal justice system, and now the chaos of their actions is showing.”

Domestic abuse commissioner Nicole Jacobs said: “Anyone who breaches a restraining order is likely to be a high-risk individual who may be fixated on their victim, undeterred by legal restrictions that have been put in place.”

She added: “Probation should not rely on an individual’s index offence to determine risk but use local intelligence to understand if there is a history of abuse and exempt them from early release on that basis.

“I am encouraged that virtually all offenders released early appear to have been recalled, and efforts have been made to rectify the error so it cannot happen again.”