One of the most important policy questions relating to the police is when, and how often, they should use guns. Police officers aren’t regularly armed in Britain, which is something to be very thankful for, especially when you see how cops use firearms in countries where they get them as a matter of routine, such as France. A shooting like the one that set off riots across French cities — where two traffic policemen stopped a man driving a car and then, when he drove off, shot him dead — couldn’t happen here. In this country, only specially trained firearms officers get issued with guns, and that has the reassuring result that traffic cops can’t kill people.

There is obviously a very pressing policy question about the regulations that dictate how our police’s specially-trained firearms officers should be allowed to use their weapons, and in what circumstances they should be punished for mis-using them. As with many matters of public policy, policy-makers have to strike a balance between conflicting objectives: protecting the public, on the one hand; and on the other, preventing the police from shooting innocent people. Wrap too many regulations around the police’s use of guns, and whilst you may ensure that the police don’t shoot innocent people, you may also ensure they don’t shoot anyone at all. That outcome would hand control of our streets to armed criminals, which is not something that anyone concerned with protecting public safety in this country could wish for.

A balance needs to be struck between regulations that are so light they produce trigger-happy cops, and ones that are so heavy they result in cops who are too reluctant to use their guns to deal with gun-toting criminals effectively.

The best way to strike that balance is primarily a matter for the police. They should be guided by the Home Secretary: this is one of those policy issues that is important enough to be decided by our representatives in Parliament. It is not something that should be determined by judges, who often rightly insist that they do not and should not make policy. Policy is ultimately a matter for elected politicians, they say. So it is, at least in a democracy.

It was consequently surprising and puzzling to see the judges on the Supreme Court last week issue a ruling, relating to the police’s use of guns, that clearly does make policy. The Court made a very definite decision on how to strike the balance between protecting public safety and reducing the chance that armed police will kill innocent people. Their decision will determine how firearms officers use their guns for years to come.

Will the public’s confidence in the police in fact be increased?

The Supreme Court’s ruling was precipitated by the fatal shooting of Jermaine Baker by a firearms officer employed by the Metropolitan Police. The killing happened nearly a decade ago. The details of the case are less important than the issues of policy that it raises. A police firearms officer thinks his own life is in danger, because he had been told, by the senior officers in charge of the operation, that the man he is to confront will be armed and dangerous. The officer with a gun sees the man make what he interprets as a threatening gesture. He fires and kills the man. Then it turns out that the man confronting him didn’t have a gun. The information the officer was given was wrong. In those circumstances, should the shooter face charges of “gross misconduct” for acting on the information he was given?

The police’s present policy is that he should not face charges of gross misconduct. The judges have decided to change that policy. They ruled that in such circumstances, the shooter should face charges of gross misconduct, along with being sacked from the police.

To get to that result, the judges had to deploy some very unusual reasoning: they had, for instance, to dismiss the Police Code of Ethics as “wrong”. Yet the Police Code of Ethics is supposed to define how officers should behave, and the standards by which they should be judged. How can it do that if it is “wrong”? Where does that leave the officers who have taken the trouble to follow it over the nine years since it was promulgated?

The judges’ decision will have a “chilling effect” on how willing firearms officers are to use their guns. They are going to be much more reluctant to open fire now that they know they can be guilty of gross misconduct and sacked, even though they acted only on information they were told by their superiors was reliable. Indeed, increasing their reluctance to fire was part of the point: the Supreme Court judges are explicit that police firearms officers who shoot and kill unarmed people need to be “held accountable” — by which they mean face charges of gross misconduct and being sacked — primarily because the judges think that will increase public confidence in the police as a whole.

Will the public’s confidence in the police in fact be increased, if firearms officers are much less willing to intervene in incidents where they might have to fire their guns and kill people?

Consider that famous case 20 years ago in a house near Henley, when the police did not intervene to help three women who had been shot by a gunman in a jealous rage. Armed, helmeted police waited on the sidelines for over an hour as two of the women bled to death because the police were not sure whether the gunman had fled the scene or that it was “safe” to enter. I doubt that incident increased public confidence in the police. The Supreme Court’s latest judgment will increase the chances that firearms officers will behave like the police did on that day.

You may agree with the judges that it is more important to have regulations that hold firearms officers accountable than it is to have armed police who are willing to use their guns to stop crime. Anything that makes cops less likely to shoot people must be an improvement, therefore. That is a perfectly intelligible view, and the judges obviously share it. Whatever view you take, however, the point is that making policy on the matter is not the role of judges. It is a matter for the police, who are ultimately accountable to our representatives in Parliament.

The Court could have made a decision that fitted best with existing regulations

The judges on the Supreme Court could have decided to hand the decision over to Parliament, as the Court has done in cases, such as medically assisted dying, when it has declined to make a ruling because it felt that to do so would be to take on a policy-making role that should be left to Parliament.

Alternatively, the Court could have made a decision that fitted best with all of the existing regulations: that would have meant, as the judges admitted, deciding that police firearms officers could not be guilty of gross misconduct when they made honest mistakes. Strangely, the judges instead ruled that “the search for coherence is simply another way of impermissibly relying on the Code of Ethics … as an aid to the true interpretation of the 2008 regulations”. That must be the first time that anyone in a position of authority has claimed that relying on the Code of Ethics is “impermissible”. If any Chief Constable were to make such a claim, he would face the sack.

Because of the Supreme Court, a firearms officer who acts on the information he has been given by his superiors will no longer be able to defend himself against a charge of gross misconduct, if that information proves to be wrong and he shoots someone who is unarmed. The change in policy will change the way the police use their guns. The Supreme Court’s decision is another indication that no matter how often senior judges claim that they don’t make policy and don’t want to, the fact is … they do.