91Èȱ¬

Overcrowding in prisons will "force" the government to change the way it deals with prisoners serving indeterminate sentences, ex-home secretary David Blunkett has said.

just under the 1,425 free cells in men's prisons needed for the system to run smoothly - jeopardizing safety and rehabilitation efforts.

Around 2,800 people are still serving Indefinite Sentences for Public Protection (IPPs), reserved for serious sexual and violent offenders, which have no end date.

Labour peer Lord Blunkett, who introduced IPPs in 2005, said "radical" reforms are necessary to address the ongoing crisis.

On Friday, the government is expected to announced plans to release some prisoners early, to ease overcrowding.

Until now, Justice Secretary Shabana Mahmood has been "incredibly cautious" about announcing reforms to IPPs, Lord Blunkett said.

But "the truth of the matter is that they will be absolutely forced" to act on IPPs to help free up space in prisons, he added.

It comes as more than 70 criminal justice experts and organisations have signed an open letter calling on the government to quickly bring in planned reforms on IPPs and consider resentencing people.

The letter to the justice secretary said: "most people serving IPP sentences and their families have lost all trust in the justice system.

"This hopelessness has had a devastating impact on the mental health of people serving IPP sentences, both in prison and in the community."

The new government must decide whether to enact reforms by the Conservative government to reduce IPP prisoners' licence time - where a prisoner is released but still under supervision - from 10 years to three.

The measures were passed in the Victims and Prisoners Act in the final hours before Parliament was dissolved for the general election but it cannot take effect until the government sets a commencement date.

IPPs were introduced in 2005 for serious sexual and violent offenders.

The sentences have no end date.

Instead. IPP prisoners serve a minimum tariff after which they can only be released, on licence, if the Parole Board is satisfied they do not pose a risk to public safety.

The sentences were abolished in 2012 after concerns they were being used too widely and that prisoners were spending many years longer than their minimum term in custody.

However, they were not retrospectively cancelled and there is an ongoing debate about what should be done for around 2,800 people who are still serving them in prison. More than 1,000 of those people have never been released.

Lord Blunkett introduced the IPPs but has since said he regretted the way they had been implemented and has called for reform.

But Alex Chalk, the Tory ex-justice secretary who oversaw the Victims and Prisoners Act, said there are "limits" to safe reforms of the scheme.

He called IPPs a "monstrous injustice" but told the 91Èȱ¬: "These people were found to be dangerous, and the parole board say they continue to be dangerous, which is why you have to proceed with caution."

A Ministry of Justice spokesperson said: “The prison system is in crisis and we recognise the significant impact this is having on our whole justice system.

“It is right that IPP sentences were abolished. The Lord Chancellor is committed to working with organisations and campaign groups to ensure the appropriate course of action is taken to support those still serving IPP sentences."