The preliminary report of the French official inquiry, published yesterday, explains one of the great mysteries of the disaster, in which 41 people are known to have died. (The death toll may yet rise further: police investigators are still sifting for human remains through the molten wreckage of 35 trucks and cars. Only eight bodies have been identified so far.)
Why did the fire get out of hand so rapidly? Fifteen previous lorry and car fires in the tunnel had been dealt with rapidly, without serious injury. The cataclysmic error made at the Italian end offers a partial answer.
While the French were sucking out fumes from one end, the Italians were blowing in fresh air from the other. The tunnel was, in effect, turned into a great, gently sloping chimney, with the flame-feeding bellows at the Italian end turned up to the maximum. It was 20 minutes before the Italians realised their error. Even then, when they tried to switch over to the fume extraction mode, their part of the ventilation system failed to work.
This was just one - clearly the most serious - of a catalogue of malfunctions, with poor Franco-Italian co-ordination and penny-pinching identified in the preliminary report to the inquiry.
All issues concerning the safety and operation of the tunnel were handled separately by the two publicly-owned, profit-making companies, one French and one Italian. Joint safety exercises were virtually unknown. The Franco- Italian "control committee" met mostly to discuss the division of the income from tolls. The possibility of excavating a series of refuges, linked by a new bore through the mountain tunnel to supply fresh air, was discussed in the early Nineties. The plan was rejected because the tunnel would have had to be closed for several weeks, with enormous loss of revenue.
All in all, the report makes dismal reading for all those who believe in European co-operation. The Mont Blanc tunnel, opened in 1965, was a great symbol in its day of the physical and political destruction of European borders that marked the Sixties and Seventies. Its phenomenal success - 800,000 trucks a year, 10 times the original estimate - is a symptom of the expansion of trade between European countries in the last three or four decades, an expansion intimately linked to the prosperity of Western Europe (Britain included).
Some of this wealth has, of course, been reinvested in improving the transport arteries on which the new Europe-wide economy depends, such as motorway systems and the Channel Tunnel. But some European figures - first Jacques Delors, latterly Neil Kinnock as EU transport commissioner - have been campaigning for years for the strategic investment of more European public cash in easing the remaining bottle necks, which are mostly at frontiers, including the obsolete and overburdened tunnels through the Alps.
The other tunnels - at Frejus and Saint Bernard, on which an even greater burden now falls - are, like the Mont Blanc, two-lane, single-bore rabbit- holes through mile upon mile of alpine rock. They, too, were conceived in a time when lorry traffic - and the lorries themselves - were much smaller than today. Although the Mont Blanc disaster did not begin with a collision between lorries, the scale of the catastrophe was caused by the sheer number of trucks passing through the tunnel.
At one time, trucks were not allowed to be closer to one another than 500m; that rule had to be quietly abandoned years ago. Twenty other trucks and seven cars travelling south rapidly accumulated behind the blazing Belgian lorry; others were trapped in the other direction. Most of the victims died in their cars or cabs. The report speculates that they were overcome by fumes and asphyxiated within five to 10 minutes, before they knew what was happening.
The EU programme of transport investment has been regularly blocked on grounds of expense. But what better use of European taxpayers' cash than to ease - and improve the safety of - the great European trade routes? The fact that a Belgian lorry was, quite innocently, at the origin of the fire and that a British driver working for a Dutch company was among those who died, puts the catastrophe in perspective. The Mont Blanc tunnel was not just a Franco-Italian disaster; it was a European disaster.
It is also instructive that the preliminary inquiry berates the management structure of the tunnel, often trumpeted as a great example of European co-operation but in fact a prime example of European non-co-operation and jealously preserved national prerogatives.
At the French end, the presidency of the tunnel company was regarded as one of the most comfortable and prestigious fiefdoms in the French bureaucracy. It was either a useful job for a bright young man on his way up, or a soft place in which to parachute a faithful old retainer. Edouard Balladur, the future prime minister, was head of the tunnel company in the early Seventies; Remy Chardon, the current French tunnel president, was head of President Jacques Chirac's office when he was mayor of Paris.
Much the same kind of people run the operations at the Italian tunnel mouth. The common denominator among all these men is that they know nothing about tunnels or transport. They are not even businessmen, who might be expected to be more aware of the comfort and safety of their customers.
The preliminary report suggests that it was crazy to have two separate companies running a single piece of infrastructure as complex and vital as the Mont Blanc tunnel.
Why, in the age of European co-operation, could there not be one bi- national company? If there had been one company with one staff and if there had been frequent tunnel-length safety exercises, the Italians might not have blown while the French sucked. The report might have added that the neither-fish-nor-foul structure of both companies - publicly owned but profit-making - has frequently proved to be a disastrous form of corporate governance.
Beyond these considerations, the tunnel catastrophe should be taken as a tragic warning - a collapsed artery near the heart of Europe. A number of studies have suggested that lorry journeys across the Alps may double in the next 20 years and that road transport in Europe as a whole may increase by 60 to 70 per cent, as more freight leaves the subsidised but inefficiently run state-owned railways. (In Britain, there has been a modest movement back from road to rail, one of the few benefits of privatisation.)
Even if the Mont Blanc tunnel reopens to lorry traffic (which perhaps it should not), the EU will face an Alpine, and possibly a Europe-wide transport crisis within a decade. It is time to consider whether more heavy-goods vehicles should be routed around the Alps, via the Mediterranean coast, or whether, Swiss-style, there should be new rail tunnels to ferry trucks through the mountains (something that is already under examination in France and Italy, but is currently regarded as being too costly).
Perhaps more freight should be forced on to the railways Europe-wide, by legislation or tax bribery or, preferably, by improving the efficiency and attractiveness of freight trains. Perhaps a large new tunnel or complex of tunnels - in the modern fashion, with an escape tunnel - should be built through the Alpine massif.
Whatever the correct solution, or combination of solutions, the issues are European issues. They should be debated at European level and, where appropriate, implemented partly with European cash.