After Richard Reid tried to ignite his shoe over the Atlantic in 2001, we all had to remove our footwear before we were allowed on a plane. That shuffling, unlacing indignity was (and sometimes still is) bad enough. But now that Umar Farouk Abdulmutallab has attempted to do the same thing to his underpants above Detroit, one can only imagine the possible consequences. What are the lingerie equivalents of slip-ons?

That the knickers bomb failed to explode properly leads a few people to conclude that al-Qaeda or its relatives are no longer to be taken seriously. It is a long time since they have attacked us successfully at home or in the sky, and it won’t take long before any new restrictions are being moaned about with the same vigour that the liquids ban attracted after August 2006. It is worth recalling, too, that between the plot and the trial there were plenty of folk willing to be very sceptical about whether there had ever been any plot at all. You know who you are.

The trouble is that a pants bomb bringing down an airliner appears to be perfectly feasible. In late August of this year, strangely under-reported here (perhaps because of the holidays), a “repentant” al-Qaeda man managed to arrange a meeting with the Saudi anti-terrorist chief, Prince Muhammad bin Nayef in Jeddah. The former terrorist, Abdullah al-Asiri, successfully passed through security checks, including airline-style metal detectors, and spent more than a day with the Prince’s security men, before gaining an audience. Then, when in bin Nayef’s presence, al-Asiri detonated around a pound of high explosives hidden in his rectum, triggering the blast with a mobile phone signal.

Fortunately, according to some sources, the blast travelled down instead of up, slightly injuring the prince. On a plane, at altitude and against the cabin wall, who knows? It is, I imagine, about as funny to be blown up by a rectal bomb as to be atomised by one in a rucksack.

A lot of people are saying that Abdulmutallab shouldn’t have been allowed to fly at all. He was on a “watch list”; his father had, reportedly, spoken to the US authorities in Nigeria about him; he bought his ticket with cash and took no luggage (both bad signs). So the simple answer, they say, is to tighten the rules about who may board and who may not.

The US no-fly list has about 4,000 names on it, and even that number requires a fair bit of administration, as those names have to be checked off every passenger list bound for the US. Most of us have been on delayed flights while this list is being scrutinised. The US Government’s TIDE “watch list” that Abdulmuttalab was on comprises more than half a million names. Any substantial movement towards including these people on a no-fly list would, surely, lead to bureaucratic paralysis.

So the best on-site security solution will have to be a huge increase in the number of the full-body scanners that we all dislike so much, which are so expensive and a fair bit slower than conventional detectors. It is one of many ironies that a consequence of the pious Abdulmuttalab’s attempt at mass slaughter will be the routine, though blurry, exposure of the nether regions of modest Muslim women (and everyone else). For those beach-towel changers who believe that other people’s chief notion of fun is catching a momentary glimpse of their pudenda, this will sound very unpleasant.

But there are other important things that the Christmas Day incident reminds us about. The first is that successful suicide bombings are still happening all the time. In Pakistan yesterday, someone thought that his path to paradise was ensured by blowing himelf up in the middle of a peaceful Shia parade through Karachi. 25 people died. On Christmas Eve in Kandahar someone else achieved self-martyrdom near a hotel, taking eight others with him. This is a truly murderous ideology, as pernicious and brave as Nazism.

The second is that there are still sufficient numbers of jihadis who persist in trying to find a way to the next 9/11 in the West, and who continually experiment with ways of achieving that great result.

The third lesson is that real “grievance” is not a measuring-stick for a likelihood to attack in this way. There are no undiscriminating suicide bombers among the world’s many environmental activists, or among the Iranian opposition. Abdulmuttalab is the well-educated son of a plutocrat, and was wealther than almost all the British people with whom he mixed. He was, however, an Islamist extremist, believing in an ideology that will always provide the fanatic with a proximate cause.

Fourth, let’s mark his family’s statement that what he did was “out of character”, as though (BBC please note) there was ever an observable character for a suicide bomber. Fifth, he has been reported as having been the president of the University College London Islamic Society. We may allow that that society does many good things, but its sequence of meetings on the “War on Terror” held in 2008, and as reported on its own YouTube video, was a clear and propagandistic attempt to cultivate Muslim anger against the West.

Fifth, Abdulmuttalab’s movements remind us of the interdependence of our world. This was a Nigerian who had studied in Britain, travelled to Yemen for training and to be fitted for his bomb, going on to Nigeria via Ethiopia, then to the Netherlands, taking a flight from Amsterdam to Detroit. It was of no interest to him whether most of the passengers were American, Dutch or British.

And sixth, though the Christmas Day bomb could have originated in a number of places, it is significant that it seems, like al-Asiri’s, to have been made in Yemen. Yemen is close to being a failed state, and this situation seems to have provided space and time for the training and experimentation needed for a plot of this kind.

This is what President Obama, Gordon Brown and the Western security services argue you would get on a far larger scale were Afghanistan and the Pakistani border areas to become Taleban nations. It is what we may still see coming out of Somalia.

In the downtime between attacks it sometimes seems that the “it’s all an exaggerated fuss” brigade has won the argument. Then, when one takes place, we lurch to the other extreme. In that time the objective truth hasn’t changed much at all.