Dominic Raab has pledged to keep dangerous criminals in prison “as long as necessary” as he takes powers to block the release of up to 100 murderers, rapists, terrorists and child killers a year.

       The Justice Secretary will announce on Wednesday that he will take back powers that allow him to overrule the parole board in the most high-profile and sensitive cases involving murder, rape, terrorism and “those who have caused or allowed the death of a child”.

       Officials will sift through more than 600 cases a year where the parole board has recommended release to identify some 100 where justice ministers led by Mr Raab will consider whether they should veto the decision and keep them locked up.

       It will be part of the biggest shake-up of the board in its 54-year history and is designed to prevent a repeat of scandals including the release of Colin Pitchfork, a double child murderer, and an abortive decision to free John Worboys, the black cab rapist.

       Mr Raab said: “Keeping the public safe is Government's first duty, and the British people expect us to keep dangerous criminals behind bars for as long as necessary to protect them.

       “I am not satisfied our approach is as robust as it needs to be, which is why I’ll be setting out plans to restore public confidence in the system.”？

       The move will restore a power to block the release of high-risk criminals that was previously held by ministers but which ended after successful legal challenges in Europe and the UK claimed it was a breach of prisoners’ human rights to let politicians rather than judges determine sentence lengths.

       The change will dovetail with post-Brexit plans already announced by Mr Raab for Parliament to get greater powers to override European judges on human rights as part of a new “British Bill of Rights”.

       Interferes with judicial independence

       The Justice Secretary is, however, likely to face legal challenges that a right to block the release of prisoners threatens the independence of the judiciary by giving the executive a role in sentencing.

       Ministers are confident, based on legal advice, that they will be able to withstand court appeals but one senior judicial source was sceptical, saying that the state would effectively be acting not only as prosecutor but also as judge and jury.

       “We will end up in a position where the Crown Prosecution Service (CPS) is going to be prosecuting someone but they want to make sure they have someone on the jury to reach the verdict they want to get,” said the source.

       “It interferes with the independence of the judiciary. It will need primary legislation and I don’t know how that would tackle the issue of [the state] effectively wanting to be judge, jury and executioner.”

       Mr Raab is also expected to tighten the criteria under which offenders are released so that, even though a parole board might judge they were no longer a threat to the public, it could be overridden if it was felt safer to keep them behind bars.

       He is demanding a more “precautionary approach” to prevent the release of offenders such as double child murderer and rapist Colin Pitchfork, who was recalled to jail for “concerning” behaviour including approaching young girls in the street.

       Mr Raab’s review of the parole board could also see victims given a new independent right of appeal. A victim or the Justice Secretary can currently challenge a parole decision by the board, as happened with Pitchfork, but this only requires it to reconsider its verdict to release the offender from prison.

       Victims will get an automatic right to apply to attend any parole board that is hearing their case although the final decision will rest with the panel’s chair.