The US and the UK then unleashed their bombs all over Afghanistan, killing far more innocent Afghans than were killed on 9/11. It did no good at all, and it certainly didn't touch Bin Laden and his team who were safely hidden in caves in the impenetrable mountains of Pakistan. Not long after Bush turned his attention to Saddam Hussein's Iraq. Less and less was spoken of the need to hunt down Bin Laden. None of this made sense. Afghanistan is now in a mess. The US and its allies are in as deep as were the previous Soviet invaders and the Taleban are as apt at keeping them on the defensive and wearing them down by a war of attrition as were the Mujahedeen 25 years ago.

Today the Western powers say their aim is to change the nature of Afghanistan society - ending militancy, liberating women, educating girls, building clinics and roads. But are we there to refashion a conservative society? That is not our business. 

And today the need to track down Bin Laden is given little consideration. Instead the firepower is aimed loosely at the Taleban, but often-innocent villagers, and in Pakistan the focus is on the leadership of the Taleban and other violent fundamentalist groups. No wonder many of us are confused.

What should have been done? There never should have been any bombing neither immediately after 9/11 nor today. The US should have chosen to run Bin Laden to earth as the wartime Allies and Israel hunted down the big Nazis who were on the run.

It was hard, dogged police work over decades. In numerous cases, including Adolf Eichmann, the concentration camps' supremo, it worked. What was needed after 9/11 was the recruitment of the most motivated Pashto speakers from the Pakistani Army, intelligence service and police force and then their training for the task ahead by the FBI and Scotland Yard. That should have been backed up by CIA and MI6 field officers working with all the tools of modern detective work (which the Israelis didn't have for their pursuit of Eichmann - forensic science, infrared capabilities and so on).

Washington and London would argue that for five years before the World Trade Center bombing they had been trying to hunt down Bin Laden and even three years before had sent operatives to Afghanistan in an attempt to encourage the leaders of the anti-Taleban opposition to capture him.

Later in 1999 the CIA trained 60 commandos from Pakistani intelligence to enter Afghanistan and capture or kill him. But when Gen. Pervez Musharraf staged his coup d'etat in Pakistan he forbade the continuance of this useful operation.

Police work and commando deployment of this kind is hard and frustrating. Yet there were also opportunities missed. In the early spring of 1996 the government of Sudan, where Bin Laden was living, made an offer to the CIA to arrest him. But the Clinton administration faltered. It passed up the possibility of bringing him to the US, believing it couldn't get a conviction in a US court and instead tried to persuade Saudi Arabia to take him in and try him. But there was an alternative, as President George W. Bush showed later - his internment on a US naval brig. Moreover, he could easily have been classed as a prisoner of war, subject to the Geneva Conventions but not to trial.

Samuel Berger, Clinton's national security adviser, revealingly told the Washington Post in 2001, "In the US we have this thing called the US Constitution, so to bring him to justice I don't think was our first choice. Our first choice was to send him some place where justice was more streamlined". 

This is how it came to be that Sudan expelled Bin Laden to Afghanistan, where he planned the bombings of the US embassies in Kenya and Tanzania, the near destruction of the American destroyer in Yemen and, finally, the devastation in New York and Washington.

Berger's account rings with contradictions. If he was convinced at the time that Bin Laden was such a danger to the US then it seems clear that the White House possessed incriminating evidence. Why did it not act upon it? Hundreds of thousands of lives could have been saved.