Prime Minister Andy Burnham is “exploring every option” to block the early release of PC Andrew Harper’s killers, according to reports.

Thames Valley Police officer Andrew Harper, 28, was killed in the line of duty in August 2019 while responding to the theft of a quad bike in Berkshire.

As the young PC confronted three teenagers attempting to flee, his ankles became entangled in a heavy-duty strap attached to the stolen bike, and he was dragged along a country road for more than a mile.

Around 5,000 prisoners are due to be released early to free up space in Britain’s prisons as part of an emergency scheme introduced to tackle overcrowding.

This is down from 6,000 following exemptions announced as part of an urgent review of the controversial scheme.

Pressure is mounting on the government to exempt Cole and Bowers from its early release scheme.

But, under current plans, Cole and Bowers remain eligible to be released halfway through their sentences.

Henry Long, who was driving the car and received a 16-year-sentence, is not eligible for early release.

A Government source told The Telegraph that the prime minister is prepared to “explore every option” to keep Cole and Bowers in jail.

It is understood the prime minister is taking further advice from officials at the Ministry of Justice on the PC Harper case.

This could include the possibility of excluding manslaughter charges from the scheme.

Mr Burnham said earlier this week he had "pushed to the very limits of what is possible to do without risking the prison system reaching capacity and collapsing" by excluding sentences for "rape, serious child sex offences and other grooming offences" from eligibility.

Early releases are set to begin from October.

Thames Valley Police has issued a statement on PC Andrew Harper's killers being eligible for early release.

Chief Constable Jason Hogg said: “I am beyond disappointed the Government is continuing to allow PC Andrew Harper’s killers to be released early from prison despite the overwhelming recent public outcry.

“It is simple: if Andrew’s killers were convicted today, they would receive life sentences due to the law that was created in his name. They would not be eligible for early release.

“This decision is demoralising for all police officers and our fellow emergency service workers, not just in the Thames Valley, that puts themselves in harm’s way to protect and serve their community.

"We stand with Andrew’s family, the Police Federation, our Police and Crime Commissioner in our dismay and we will continue to lobby the Government to make the right decision.”

PC Harper’s family have also voiced fury at the prospect of Cole and Bowers being released from prison early.

Lissie Harper, PC Harper’s widow, who campaigned for legal changes to see harsher sentences for the manslaughter of emergency workers on duty in the wake of her husband’s death, described the prospect as “deplorable”.

"It has taken me years to rebuild a life that was torn apart in a matter of moments,” she said.

"Now - once again - politicians are making decisions from behind a desk that will have real and lasting consequences for victims' families like mine.

"It is deplorable to me that we have reached a point where releasing prisoners early is even considered acceptable. We speak of justice, accountability and standing with victims, yet decisions like this do the opposite.”