Thames Valley Police Chief Constable Jason Hogg has said he is considering joining legal action to block the early release of two men convicted over the death of PC Andrew Harper.
Hogg said he was in discussions with the Police Federation of England and Wales and described public opposition to the potential release as "overwhelming."
PC Harper was killed in 2019 while responding to the theft of a quad bike in Berkshire. He suffered fatal injuries after being dragged behind a vehicle as three teenagers fled the scene.
Passengers Jessie Cole and Albert Bowers were convicted of manslaughter in 2020 and each received 13-year prison sentences, making them eligible to apply for early release after serving half their terms.
The driver, Henry Long, was sentenced to 16 years in prison and is not eligible for early release.
Speaking to the BBC, Hogg urged the government to reconsider its policy, noting that prisoners convicted of manslaughter remain eligible for early release, unlike those convicted of offences including murder, rape, terrorism and serious child sex offences.
"I fully understand the challenges around the crisis in the prison system," Hogg said.
"But the decision made and where that line has been drawn, I do not believe that people responsible for taking the life of another citizen in our country should be released early."
He said the Police Federation was considering legal action and confirmed he would consider joining any challenge after obtaining legal advice.
Following Harper's death, Parliament passed Harper's Law in 2022 after a campaign by his widow, Lissie Harper. The legislation introduced mandatory life sentences for those convicted of killing emergency workers and increased the maximum sentence for assaults on emergency service personnel.
However, the law does not apply retrospectively and therefore does not affect the sentences imposed on Harper's killers.
Thames Valley Police Federation chair Aileen O'Connor said the organisation would pursue legal action if advisers concluded there were grounds for a challenge.
Sentencing Minister Jake Richards defended the government's position, saying it would be unlawful to single out individual cases for exclusion from the early release scheme.
He confirmed that manslaughter convictions remain outside the list of offences exempt from the policy.
The government has said around 5,000 prisoners will be released early in phases from October as part of measures to address prison overcrowding, while approximately 1,000 prisoners will remain in custody following recent revisions to the scheme.
