The senior investigating officer in the PC Andrew Harper case has told BBC Breakfast he is “appalled” that two of the killers will become eligible for early release.

PC Harper, 28, from Wallingford, Oxfordshire, died from catastrophic injuries in 2019 when he was dragged behind the getaway car of three teenagers who had fled the scene of a quad bike theft.

Two of his killers – Jessie Cole and Albert Bowers – will be eligible for early release next year under revised government plans to tackle prison overcrowding.

Stuart Blaik, who investigated the killing, said it was “particularly hard to understand” their case for early release and said police officers were shocked at the prospect.

PC Harper’s widow, Lissie Harper, has been among a growing number calling for Cole and Bowers to be denied early release from prison.

Defence Secretary Wes Streeting told the BBC on Friday that early release is “not okay” – adding that no government should have been put in the position of having to deal with limited prison capacity.

Speaking to BBC Breakfast on Friday, former Det Sup Blaik, who led the Thames Valley Police investigation, pointed to remarks by the judge who sentenced PC Harper’s killers. Mr Justice Edis referred to their case of manslaughter as being “very close to a case of murder in its seriousness”.

The former officer called for prisoners who were judged to have had a high level of culpability for a manslaughter offence to be excluded from the scheme.

Allowing them to walk free would “undermine” the judicial process and impact police morale, Blaik said, before urging the government to have a “long, hard think” about the case.

The former Det Sup left Thames Valley Police in 2023. This is the first time he has publicly shared his views on the issue.

Streeting said the government is taking the issue “extremely seriously”.

“We should never have been put in a position where prisons across the country were so full-to-bursting that any government, let alone this government, had to contemplate the early release of people from serious convictions that have led to being in prison in the first place.

“We’re not pretending this is okay.”

He pointed to “strong controls” and supervision that will be in place for people released into the community and added that the government is “determined” to build more prison places and is looking carefully into the exemptions under the scheme.

In an earlier statement given exclusively to BBC Breakfast, former Det Sup Blaik said “like many people across the country” he was “deeply concerned and appalled” by the prospect of Bowers and Cole being considered for early release.

He said that because the “death of Andrew was such a serious and tragic case”, Bowers and Coles should “not be afforded the opportunity” to be released early.

“Neither of them showed any remorse during their time in police custody or during their subsequent trial.

“I hope the Government takes account of the strength of public feeling on this issue, which has been both clear and widespread,” he added.

Under revised plans announced by the government on Monday, prisoners who have committed rape, grooming, and serious child sex offences will be excluded from an early release scheme for England and Wales.

But those guilty of manslaughter may still be eligible.

An average of 150 people a year are sentenced at crown court for manslaughter with an average term of nine years. That means that in any given year there are hundreds of these offenders in jail. If they were all kept in, that would eat into the available spare beds – a number that is declining despite the massive prison-building programme.

If the government were to try to differentiate between different types of manslaughter offenders based on the specific nature of the crime they committed, that could be legally complex to deliver – and may in turn face serious legal challenges from prisoners who find their release dates changed.

Bowers and Cole were sentenced to 13 years for the manslaughter of PC Harper.

They will become eligible for release from prison after serving half of their sentences under the plans, instead of two-thirds.

The driver of the getaway car, Henry Long, was jailed for 16 years for the same offence. But Long will not be eligible.

PC Harper and Lissie had been married for just a month when he was killed in the line of duty.

On Thursday, the police officer’s widow said she “will not give up” and hoped people would share a petition calling for his killers to be denied early release from prison.

She said: “Hopefully we can make the current government come to their senses and realise we cannot put people like this back on our streets.

“Justice should mean justice and serving the sentence given.”

Thames Valley Police Federation chair Aileen O’Connor began the petition this week.

“My ask is that the prime minister, the home secretary and everybody else in government gets on the right side of this and does the right thing and makes the changes that keep the two killers behind bars,” she said.

“We have been working closely with Chief Constable Jason Hogg and Police and Crime Commissioner Matthew Barber from the outset on this.

“We are all united in our frustration and dismay at the government’s ridiculous plans when it comes to releasing from prison early the killers of police officers.”

The government said it was trying to avoid running out of prison spaces as soon as October this year.

The justice secretary Alex Norris previously said about 1,000 prisoners would now not be released early following the revision to the scheme.

“If we drew it any wider we would have a prison capacity crisis,” said Norris.

Prisoners released on licence, he said, would be subject to “very significant controls on their lives” and victims would be consulted.

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