A profoundly important, unprecedented and dangerous decision has been taken by European leaders in the past few days. It’s not made as explicit as it should be – because our leaders are always careful to erect a bodyguard of verbiage and lies to protect them if something goes wrong – but it’s perfectly clear that they want any foreign fighters in Isis to be killed when they are found. It’s not a question of whether they deserve to live or die – they have cut the throats of innocents, including my journalist colleagues, and they have raped women and enslaved children. We know that, and we are aware that their vicious cult has not yet ended. Isis is still alive.

But what happened to justice, that staple foundation of all countries that believe in freedom, democracy, liberty? A few quotations to start with. Here is the French minister of the armed forces, Florence Parly. “If the jihadis perish in this fight, I would say that’s for the best,” she said. Then we have the US envoy for the anti-Isis coalition, Brett McGurk. “Our mission is to make sure that any foreign fighter who is here, who joined Isis from a foreign country and came into Syria, they will die here in Syria. So if they’re in Raqqa, they’re going to die in Raqqa.”

And here is our very own diplomat-philosopher and Tory minister Rory Stewart. “These are people who have essentially moved away from any kind of allegiance towards the British Government … they believe in an extremely hateful doctrine which involves killing themselves, killing others and trying to use violence and brutality to create an eighth century, or seventh century, state. So I’m afraid we have to be serious about the fact that these people are a serious danger to us, and unfortunately [sic] the only way of dealing [sic again] will be, in almost every case, to kill them.”

Shocking photos emerge of suspected Isis fighters held in overcrowded prison

Now this statement by Stewart – normally a fairly sane television personality who can explain Middle Eastern history – is perfectly understandable, utterly lucid and totally deplorable. Stewart, Parly and McGurk are effectively calling for the execution of their citizens who have joined Isis. They don’t say this, of course. And the Germans have actually stated that any German citizens will have consular assistance if necessary – they, of course, have to avoid the SS smell for all the obvious reasons. But we are telling Iraqi soldiers and militiamen and Kurds and anyone else that they can kill British or French or US citizens who have joined the dark and wicked forces of Isis. Fine. No probs. Who cares to take them back? And if we allowed Brits in Isis to come home, who knows how many hijackings and mass murders would take place in an attempt to free them from prison. But what happened to international justice?

When George W Bush talked about bringing the bad guys to justice after 9/11, I wrote that I very much doubted if any justice would be coming Osama bin Laden’s way. And I was right. He was assassinated by the Americans. And nobody, naturally enough, complained about it. Live by the sword, die by the sword. But bin Laden’s death – and the ocean of drone attacks that followed – gave a gently, dark signal that it’s OK to murder these bad guys. Forget about courts, evidence, trials, justice and the rest. Just obliterate them. Who is going to complain?

But we should complain about this wretched and despicable policy. For decades, we have been condemning the dictators of the Middle East for their savagery, for their drumhead courts and their mass hangings – and rightly so. But how can we condemn them now, when we are announcing, quite publicly, that we want our own citizens dead if they joined – or are believed to have joined, or might have joined, or are said to have joined – Isis. If we are now, in effect, calling for their execution, then we have no more right to lecture any tyrant about their wickedness. The Egyptians and the Saudis and the Syrians can now chop off heads or hang or slaughter anyone they want on the basis that the “only way of dealing” with them (“unfortunately”, of course) will be “to kill them”.

Now if a Brit chooses to fight and die in battle for a grotesque organisation like Isis, that’s his (or her) problem. But if captured, should we not “deal” – how I love Stewart’s phraseology – with them by administering real justice, locking them up forever if that’s the sentence, giving them their day in court, showing for all the world that we are not killers and that we have a higher morality than the murderers of Isis? Right now, the Egyptians are “disappearing” prisoners. Last weekend, militants – which we can sensibly assume were Isis – massacred more than 50 police officers south-west of Cairo. It was a disaster which the Egyptians would like to cover up. The dead included two brigadier generals and 11 colonels. They were themselves trying to ambush the militants but it all went wrong, presumably because Isis have an informer inside the police. But when Isis members (or presumed Isis members) turn up dead on the streets of Egyptian cities in the coming days, are we in any position to talk to Field Marshal/President Sisi about justice?