Lord Thomas of Cwmgiedd, who was the most senior judge in the jurisdiction between 2013 and 2017, worries that those imprisoned under the abolished imprisonment for public protection (IPP) sentences will be “left to rot” in jail. He is backing The Independent’s campaign for IPP prisoners to have their sentences reviewed.

The sentences, under which offenders are given minimum terms but no maximum, were abolished in 2012, seven years after they were introduced by Labour.

Their abolition did not, however, apply retrospectively, meaning thousands of people are still jailed without a release date until the Parole Board deems them safe to be allowed out.

Of the 2,374 IPP prisoners who are still imprisoned, more than 700 have been in jail for 10 years more than their minimum term. At least 90 IPP prisoners have committed suicide.

Crossbench peer Lord Thomas, 76, said: “I think everyone accepts this punishment was a mistake. It’s just morally wrong.”

He called for changes to the parole release test, with a greater focus on the proportionality of the punishment to the crime.

He said: “You can’t say, ‘Oh, they have been in a long time and now they are dangerous – and because we have made them dangerous, we can’t release them.’ I mean, you have to accept a degree of state responsibility. However you look at it, it is the state that’s caused this problem.”

Had they committed their crimes today, prisoners would have been given a fixed sentence.

One prisoner, Thomas White, set himself alight after serving more than 12 years for stealing a mobile phone. Another, Abdullahi Suleman, has spent 19 years in prison for stealing a laptop.

“These people are just unlucky that their crime was in that seven-year period that this sentence was in force,” Lord Thomas added.

Andrew Neilson, director of campaigns at the Howard League for Penal Reform, said: “The IPP scandal is still a long way from being resolved, and the sentence continues to inflict misery on thousands of people still trapped in the prison system, and their families.

“The Howard League continues to work for and alongside those directly affected by this disastrous sentence, and we have been thrilled that our recently established IPP hotline has already been able to provide help and support to so many. We will continue to campaign and make the case for urgent IPP reform, and continue our work to address the plight of people still languishing in custody.”

A Ministry of Justice spokesperson said: “It is right that IPP sentences were abolished. We are significantly shortening licence periods for rehabilitated offenders, to give them the chance to move on with their lives. With public protection as the number one priority, the lord chancellor is working with organisations and campaign groups to ensure appropriate action is taken to support those still serving these sentences.”