After a day of briefings in Kabul, our friendly Nato hosts flew us by military transport to Herat, on the western border with Iran. We were due to spend a day touring a Nato post in the city and then fly back that evening to the capital. But the Danish plane that had taken us developed propeller problems and was grounded. As we cooled our heels outside the airfield , we waited for word of the aircraft that was supposed to come for us: a German C-130.

It soon became clear that the replacement plane was not coming. The reason, it turned out, was that the Germans would not fly in the dark. German aircraft are not permitted by their national rules to undertake night flights.

Now to those who survived the Blitz and Barbarossa, the news that today’s Luftwaffe will not fly at night in potentially hostile environments might be regarded as a welcome historical development. But when you are trying to fight a war against a ruthless band of terrorists who operate 24/7, never pausing to consider the dangers of venturing out in the dark, limiting yourself to daytime operations is a little constraining.

The Germans are not alone. Many of the European nations with forces in Afghanistan are operating under similarly ludicrous restrictions. Though their soldiers and airmen are highly capable and indeed eager to take the fight to the Taleban, their governments are desperately fearful of the public reaction should their soldiers suffer significant casualties. They don’t think that their voters will stomach it. And the tragedy is, they are probably right.

I was reminded of my unscheduled night in Herat, and what it said about Europe’s dwindling commitment to its own survival, by a series of disheartening developments in the past week on the political and diplomatic front.

Last week we had the tragicomic spectacle of European Nato countries lining up to decline politely the request to beef up their forces in Afghanistan, many of whom are now fighting in perilously under-resourced conditions against a resurgent enemy.

Then on Monday Jacques Chirac went to New York to upend the long, delicate diplomacy designed to deny Iran nuclear weapons. He said France no longer thought the UN should impose sanctions if Iran did not end its uranium enrichment programme.

Various explanations were offered by commentators for this volte-face — from the thought that France might be fearful of the economic consequences of sanctions, to the possibility that M Chirac was trying to curry favour with sanctions-opposing Russia and China, to the suggestion that Paris worries that its new peacekeeping force in Lebanon might come under fire from Hezbollah if France acted tough with its Iranian sponsors.

Whatever the proximate cause of this latest French surrender, the basic reality is that Europeans have been extremely reluctant to press Iran with sanctions all along — the same noises are coming out of Berlin now — and are content instead to acquiesce in the nightmare of a nuclear-armed Tehran.

Then, of course, we have had the predictable European outrage following the latest apparent provocation of Islamic extremists by free speech in the West — Pope Benedict XVI’s remarks last week on Islam.

I actually heard a senior member of the British Government chide the Pope this week for what he described as his unhelpful comments. This minister went on to say that the Pope should keep quiet about Islamic violence because of the Crusades.

It was a jaw-dropping observation. If it was meant seriously its import is that, because of violence perpetrated in the name of Christ 900 years ago, today’s Church, and presumably today’s European governments (who, after all, were eager participants in the Crusades) should forever hold their peace on the subject of religious fanaticism. In this view the Church’s repeated apologies for the sins committed in its name apparently are not enough. The Pope has no right, even in a lengthy disquisition on the complexities of faith and reason, to say anything about the religious role in Islamic terrorism.

It is apt that Pope Benedict should have received such European opprobrium for his remarks. His election last year looked like a final attempt by the Church to revive the European spirit in the face of accelerating secularisation and cultural morbidity.

But the scale of Europe’s moral crisis is larger than ever. Opposing the war in Iraq was one thing, defensible in the light of events. But opting out of a serious fight against the Taleban, sabotaging efforts to get Iran off its path towards nuclear status, pre-emptively cringing to Muslim intolerance of free speech and criticism, all suggest something quite different.

They imply a slow but insistent collapse of the European will, the steady attrition of the self-preservation instinct. Its effects can be seen not only in the political field, but in other ways — the startling decline of birth rates across the continent that represent a sort of self-inflicted genocide; the refusal to confront the harsh realities of a global economy.

It may well be that history will judge that Europe’s decline came at the very moment of its apparent triumph. The traumas of the first half of the 20th century have combined with the economic successes of the second half to induce a collective loss of will. Great civilisations die not in the end because of external force majeure but because internally the will to thrive is sapped.

The symptoms of this moral collapse may be far away from the affluent and still largely peaceful cities and towns of the old continent — in the mountains of Afghanistan, the diplomatic reception halls of Tehran and the angry Pope-effigy-burning streets of the Middle East. But there should be no doubt that it is closer to home where the disease has taken hold.

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