It was one of Andy Burnham’s earliest decisions as prime minister, and one that apparently showed a commendable sensitivity to public opinion.

In July, when it first emerged that the government’s prisoner early release scheme would result in the untimely freedom of two of the men responsible for the killing of PC Andrew Harper, there was an understandable backlash. The new prime minister called a halt to the process and demanded a review. So far, so good.

Yet now, having gone through the review with his ministers and civil servants, the prime minister has somehow emerged with the two notorious killers still set to be freed in a matter of weeks, snatching a costly political mistake from the jaws of a victory. The Harper family and their campaign, public opinion, the whole of the media, the opposition parties, the Police Federation and now the head of Thames Valley Police, Chief Constable Jason Hogg, are against Mr Burnham.

The circumstances of PC Harper’s death were particularly distressing. The young officer, just 28, was fatally injured after being dragged for a mile behind the men's car along a country road while responding to a burglary in Sulhamstead, Berkshire, in August 2019. PC Harper and his wife, Lissie, had been married for less than a month.

It shocked the nation, as it still does, and soon led to a change in the law and longer sentences for fatal assaults on emergency workers. No wonder there was an outcry when the full consequences of Keir Starmer’s plans to release up to 6,000 offenders from prison early in September, amid official predictions that prisons will be full in November, became clear.

But here was Mr Burnham, in the best traditions of a big city mayor, responding to those concerns and the feelings of the officer’s family, friends, and colleagues. The unspoken message was that the new man in Number 10 wasn’t going to be tied down by lawyerly concerns, and would put people first.

This subsequent own-goal is perplexing. Convictions for manslaughter have fluctuated between 144 and 196 per year for the last decade. The number currently incarcerated – a number which is not published – must therefore be relatively modest compared to the overall prison population and, indeed, the scale of the release programme.

Obviously, lines must be drawn somewhere, but a determined prime minister with an eye for public sentiment would tell his officials that those convicted of the manslaughter of a police officer should be excluded from the early release programme, as is the case for murderers, sex offenders, grooming gang members, domestic abusers and rapists.

What is more, even if those in the manslaughter category made the critical difference to the viability of the early release scheme, the prime minister should still have insisted.

There are also some 2,400 people held under the defunct imprisonment for public protection (IPP) regime; many of these could be let out on bail, tagged and supervised. Older disused prisons could possibly be partially recommissioned. The implementation of the new sentencing act could also be delayed until it can be swiftly amended immediately when parliament reassembles next month. Ways can always be found, even if they are expensive and necessarily temporary.

To make matters worse, Mr Burnham has chosen this moment to go on holiday, after 15 days in the job. Leaving this business unsettled neither feels nor looks right.

The temptation must be for Mr Burnham to bow to the inevitable and execute his first U-turn, even if it has to be done remotely from his sun lounger. But that does raise some uncomfortable questions about his judgment and competence, as well as his ability to stick to a position and face down resistance. It is thus a lose-lose for Mr Burnham.

That said, it is now advisable that he should move quickly to stop PC Harper’s killers being let loose again, and thus move on to the more strategic matters that will define the success or otherwise of his time in office. Done rapidly, this should not turn into Mr Burnham’s version of the winter fuel payment debacle that lingered and so disoriented Sir Keir Starmer’s administration from the outset.

As they say in Whitehall, there will be “lessons learned” for all concerned from this mishandled move. Of course, it is only fair to add that the fundamental problems of overcrowded prisons were caused by decades of underinvestment, most grievously during the coalition’s “austerity” drive.

There will also always be some dismal criminal set free in an emergency release scheme who will reoffend and hit the headlines. Such things are outside the control even of a prime minister. But the more obvious blunders and scandals can be avoided, and this is one of them. In due course, Mr Burnham will need to explain why he got this decision so wrong.