A Police Federation chief has threatened to haul the new Prime Minister into court to stop the "betrayal" of Jessie Cole and Albert Bowers being allowed out within weeks.
Thames Valley Police chair Aileen O’Connor said Burnham’s decision to allow killers out early was “an insult to Andrew’s family, friends and colleagues” and said, “Andy Burnham may be on his holidays but we won’t rest on this.”
PC Harper’s family, including his campaigner widow Lissie, are said to be supportive of the move.
Mr Burnham had reportedly hoped to block early release for manslaughter convictions, but is said to have decided that prisons are too full to do so.
This means that Cole and Bowers, who were passengers in the car which killed PC Harper, will still be eligible for early release from October.
This comes despite Lissie Harper’s campaign being a major factor in a review which saw rapists and child sex offenders stopped from being released early.
Writing in The Sun, Ms O’Connor challenged the PM and Justice Secretary Alex Norris to stand before Lissie and his family to “explain why those responsible for killing a police officer should be eligible for early release”.
She adds: “Try telling the officers who attended the scene where Andrew died and witnessed the horrific consequences of that crime.”
She told LBC News: “I will throw everything I can at this through a proper legal challenge from KCs, barristers, you name it. I will do what
“I have to do to protect Andrew Harper’s legacy and further victims who don’t have a platform to come on national radio or TV to put across their point.
“There are silent victims here in the families of individuals who have been killed who will also be outraged at this.”
A petition launched by Ms O’Connor passed 100,000 verified signatures on Tuesday evening.
After 100,000 signatures, petitions are considered for debate in Parliament.
Ms O’Connor added online: “This decision pours salt into wounds that have never healed.
“It is an insult to Andrew’s family, his friends, his colleagues and the entire policing family.”
She added: “I don’t feel like we should be in this position. It’s not somewhere we would expect to be.
“We really feel we should have more support than this and, you know, Andrew deserves better than this and so do we.
“I think from our perspective we need to know that people are going to be keeping in touch and letting us know what’s going on.”It means offenders on standard fixed sentences and due to be released after half their term will now leave after a third.

World Affairs Correspondent