9/11 anniversary: How the lessons of the attacks are still being learnt

Spies, strategies and missed opportunities: How the lessons of 9/11 are still being learnt

The first duty of a government, countless leaders over the decades have said, is to safeguard its population. On 11 September 2001 the US manifestly failed to do that. The intelligence was there, yet tragically, nobody joined up the dots in time.

On 11 September 2001, as al-Qaeda's suicide pilots flew those hijacked planes into the World Trade Center, I was just finishing a deployment in our Middle East bureau. As a Palestinian taxi driver drove me through the pine-clad hills west of Jerusalem to Tel Aviv's Ben Gurion airport he suddenly turned up the car's radio. "Something big has happened in America," he said. He wasn't exaggerating. 2,977 victims died that day.

Nine days after the 11 September attacks, then US President George W Bush declared the "War on Terror".

In the ensuing 25 years there have been numerous intelligence successes as well as failures on both sides of the Atlantic. The successes include plots that have been foiled, suspects who have been arrested, brought to trial, convicted and jailed.

No one can question that 9/11 was a colossal intelligence failure, or to be more specific, a failure of imagination in the US intelligence community. At the time both the CIA and the FBI were in possession of information which, if shared properly, could have prevented what happened.

This most basic of lessons has since been largely – although not completely – learnt, and sharing between Western intelligence agencies is infinitely better than it was in 2001.

Since 9/11, there has also been a root-and-branch reorganisation of US intelligence with the establishment of a National Counter Terrorism Center just outside Washington DC and a Director of National Intelligence to ensure that information is shared where it needs to be between the 18 separate US intelligence agencies. The relationship between the CIA and its UK counterpart, the Secret Intelligence Service (better known as MI6) is perhaps the closest one in the world. This is supplemented by the Five Eyes alliance that pools intelligence between the US, UK, Canada, Australia and New Zealand.

Against a backdrop of overwhelming political pressure from Washington to produce evidence that Iraq, under its President Saddam Hussein, still possessed Weapons of Mass Destruction (WMDs), MI6 supplied Prime Minister Tony Blair's government with what turned out to be flawed intelligence. Iraq did indeed have WMDs in the past, but it was all destroyed after the 1991 Gulf War.

"The [2003] Iraq war was based on deeply flawed intelligence," says General Sir Richard Shirreff who served in Iraq as a divisional commander. "Have we learnt from it? No, I think we're bad at learning… It was so obvious as a Commander that we were heading for strategic failure".

The Security Service, MI5, has also had its own failures, amid numerous undoubted successes, in foiling terrorist plots. "After 9/11," says Lord Jonathan Evans, who ran MI5 from 2007-2013, "the assessment was that by far the most pressing security threat to the UK was the terrorist threat from al-Qaeda and associated individuals and groups".

But with a database back then of more than 20,000 "Subjects of Interest" and a high number of investigations running concurrently, MI5 faced – and still does – a daily challenge of which leads to prioritise. It has not always got it right.