The Government has apologised to the family of Pc Andrew Harper as two of his killers remain eligible for early release.
Justice Secretary Alex Norris acknowledged that the decision had “created harm” but said the alternative was seeing prisons cease to function.
Some 5,000 people are expected to be released early under sentencing changes, down from 6,000 after ministers exempted rapists and child sex offenders as part of the scheme to tackle overcrowding in jails.
But two of Pc Harper’s killers, Jessie Cole and Albert Bowers, remain eligible for early release after their 2020 convictions for manslaughter despite an outcry from the officer’s family that prompted a review of the early release plans.
The 28-year-old police officer sustained fatal injuries while responding to a quad bike theft in Sulhamstead, Berkshire, in August 2019.
He died after getting caught in a strap attached to the back of a car and dragged down a country road as three teenage suspects fled the scene of the burglary.
The driver of the vehicle, Henry Long, received a 16-year sentence and would not have been eligible for the Government’s scheme, but Cole and Bowers were sentenced to 13 years and are now eligible to be released halfway through their sentences.
Pc Harper’s wife Lissie Harper has expressed anger at the prospect they could be released early, calling it “an affront to justice” and “an utter betrayal”.
His mother, Debbie Adlam, said the family was “bitterly disappointed” by the decision, telling the BBC: “Andrew deserves better than this, and so do we.”
Mr Norris said he understood the family’s “anger” and offered an apology, but added the early release scheme was necessary to avoid the collapse of the prison system.
He told Sky News: “Were we not to make these changes, then we would run out of prison places in this October or November.
“I know that’s difficult. I know that’s created harm, and it’s not Lissie Harper’s fault, and I’m sorry that she’s been put into this situation as a result, I genuinely am.
“But this is a decision we’ve had to take to make sure we have a functioning prison system.”
Ministers announced on Monday that rapists and serious child sex offenders would be exempt from the early release scheme, after a review of the policy ordered by Andy Burnham shortly after he became Prime Minister.
Mr Burnham said he had wanted to “go further” with the exemptions, but this was “not possible without the prison system reaching capacity and collapsing”.
The releases, which had been planned for September, have also been put back to October to allow the probation service more time to prepare.
Those released will face tougher probation conditions, including electronic monitoring, random drug testing and possible bans from driving, pubs and events such as football matches.
The changes were part of the Sentencing Act passed earlier this year that cut the minimum amount of time many offenders would have to spend in prison.
Labour said the changes were needed in part because the Conservatives had left the prison system “at breaking point” because of overcrowding.
Mr Norris said the policy meant that the Government would not need to repeat the early release schemes that had previously been necessary to avoid prisons becoming full.
The Government has also said it would build 14,000 new prison places by 2031, with 3,000 already delivered in the past two years.
But the Conservatives have said victims “deserve better”.
Kemi Badenoch said her party would build more prison places, rent cells abroad and deport foreign offenders to ease overcrowding.
She told broadcasters: “We do need to solve the problem of prison overcrowding. We said we were going to build prisons in the Conservative manifesto, Covid derailed that programme.
“We still need to build prisons. We need to remove foreign criminals, and we should do what Conservatives had planned to do two years ago, which Labour stopped, which is rent prison spaces from other countries. Sweden does it. The UK can do it too.”
Asked how much that would cost, she said: “You cannot put a price on keeping the citizens of this country feeling safe and secure.”
Nigel Farage said Mr Burnham “tells people what he thinks they want to hear” but “will not actually deliver”.
“Andy Burnham said it would be awful if Pc Harper’s killers were released early. But he’s now letting it happen,” the Reform UK leader said.
“Both Labour and the Conservatives have failed us all.”
The Liberal Democrats demanded the Prime Minister “step up” and act to prevent Pc Harper’s killers from being released early.
“It is an insult to the family and loved ones of Andrew Harper that his killers are still eligible for early release after committing such a heinous crime,” the party’s justice spokeswoman Jess Brown-Fuller said.
“Ministers repeatedly assured Parliament that the most serious offenders would be exempt from these measures and it is clear that is simply not the case.”
The Prison Governors’ Association (PGA) also criticised the late change to the policy, saying it had put “huge pressure” on prison staff, making mistakes “more likely”.
PGA president Tom Wheatley said: “Government needs to decide on a direction and stick to it, changing course at a late stage causes scarce resources to be used unnecessarily and puts prison and probation staff under extreme pressure.”