lumnist fears putting into published words what some ghoul might take up as an idea upon which to act.

Anyway, it doesn’t matter where. Actually it doesn’t matter that the visibility was reduced by fog. Even in clear daylight a train driver must travel at speeds whose corresponding stopping distances far exceed visibility. If line-side signalling were audible instead of visible then, for all the difference it would make, locomotives could be driven for much of their journey with the windscreens blacked. Docklands Light Railway trains in London have dispensed altogether with drivers.

Speeding along through the September fog, then – flying blind – I was struck (as any railway passenger must often have been) by this thought.

A concrete block is easily procured. A pair of wire cutters can be bought across the counter in any DIY shop. High-speed rail tracks can be accessed easily and discreetly in innumerable lonely places across the country. I forbear to say more.

In an age in which the modern mass media are believed to probe every nook and cranny of human thought, holding nothing back, there persist vast and inexplicable divides between what people actually think and feel, and what broadcasters and journalists depict as our habits of mind and sentiment. There are huge questions, huge “I wonders” that rarely find their way into publication. One of these has nagged at me since the IRA terrorist scares of the 1970s, ’80s and ’90s, and throughout the so-called War on Terror; and I should be surprised if it did not nag millions of my countrymen too. This is not the question of why terrorists do the things they do. It is the question of why they don’t do more.

Doing more would be so easy. In an open society like ours the national throat is open and exposed for the cutting in a hundred places. A small amount of explosive beneath pylons in a million unguarded locations will bring down a high-tension power supply. A drop of poison at a thousand access points to our water supplies could kill hundreds. A brick dropped from a motorway bridge on to a coach’s windscreen combines a good chance of murder with minimal risk of capture. Our railways are essentially unguarded.

Such atrocities – every reader will have his or her own list – have no need of suicide merchants for their execution. For explosions any crude timing device will do: why should the bomber blow himself up too, unless he wants to? Many could be attempted with something close to impunity.

They do not require hundreds of gallons, carefully hoarded, of hydrogen peroxide in Germany, or complicated cavities inside shoes, or advanced electronics.

The easier kind of hit does occasionally occur. Lunatics, vandals and (less often) serious political activists have been known to attack infrastructure and life itself in some of the easy ways. But on the whole, terrorists choose the difficult ones. And, matching their arrows with our armour, we guard the difficult ones.

Is there some strange way in which this satisfies both? Is there a kind of unconscious agreement? Are we and the terrorist supplying for the fight a title that satisfies the vanities of both teams – “War” on “Terror” – then choosing the domain and battleground where fixtures are to be played: exotic venues such as jets, subterranean railway tunnels, nightclubs, packed commuter terminals; and finally agreeing even on a pair of mutually opposed and appropriately impossible outcomes counting as the knockout win that both half-fear: the Destruction of the West vs the Elimination of Terrorism? Is there a creepy, subliminal pact? I ask not rhetorically – this really is a question – but because I have noticed a series of clues for a riddle to which this could (I emphasise could) be an answer.

The first clue is something that has mystified me about politicians ever since I first became one. Few of them are at all interested in government. By “government” I mean not grand debates about national destiny, but sound, capable, efficient public administration: the effective running of the country. This has to be the first thing politics is for – without it what else can be achieved? – yet had you been privy to the countless private, informal social chatter between practising politicians to which I’ve been witness, you would be amazed at how weak is the interest of most of them in running things. My own great concern, transport, is regarded within both the Conservative and the Labour parliamentary parties as the province of nerds and also-rans.

The second clue lies in the parallels between the enthusiasms, analysis and commentary aroused by politics, and those of the world of sport. For us political commentators, general elections are World Cups.

Referendums, local, European and intra-party elections lie in the lower divisions. We stay up all night to watch (for fun alone: we don’t need the results until morning); we even record and replay classic political matches. Listen to political enthusiasts talking among themselves. You will see I’m right.

The third clue is related: our obsession with public performance as a measure of political calibre. Prime Minister’s Questions becomes a kind of Match of the Day.

The fourth clue is the fascination that conflict holds for politicians and their hangers-on. Elections are one kind of joust, of course, but rows and contests of every variety – economic summits, stand-offs between nations, and finally, of course, wars – are what rivet the politico’s attention. Curious, because in terms of human administration, conflict is usually a sort of failure, often on both sides.

And the fifth clue was where I started: my suspicion that terrorist movements do not act rationally in the targets they choose, and governments do not always respond rationally, instead playing things up rather than down and reinforcing defences of what terrorists nominate as targets. Were al-Qaeda to strike next by reintroducing foot-and-mouth disease into Britain, I have a suspicion that both sides – including violent Islamists – would have the uneasy feeling that this was cheating: unsporting, like dynamiting fish.

As a schoolboy I used to wonder why pivotal battles in history seemed to take place on agreed grounds at an agreed time according to agreed rules. Why Hastings? Why Verdun? Why Trafalgar? Why not kill the French sailors when they tried to come ashore? I still wonder. And now I begin to wonder whether the War on Terror, too, has subliminal echoes of a sporting series, with fixtures, scoring systems and rules mutually agreed. Do we really want what we think, say and sincerely believe we want. Does the young Islamist? Or are we all enjoying this?