25 Years After 9/11: How Intelligence Agencies Still Grapple With Strategic Failures

Twenty-five years after the planes struck the Twin Towers, the intelligence agencies of the West have learned to talk to each other. They have reorganized, created fusion centers, established new oversight bodies, and built systems designed to ensure that the pieces of information scattered across different desks and different countries actually find their way to the same table. And yet, on the fundamental question—whether they can see what is coming—the answer remains uncertain.

On September 11, 2001, the CIA and FBI possessed fragments of the plot that would kill 2,977 people. They knew about al-Qaeda. They knew about Osama bin Laden. They had a taskforce dedicated to tracking him. But the information never connected. The 9/11 Commission Report later called it a failure of imagination, policy, capabilities, and management. It was, in the plainest terms, a colossal intelligence failure at the moment when the first duty of government—to protect its people—mattered most.

The reforms that followed were substantial. The US established a National Counter Terrorism Center outside Washington and created the position of Director of National Intelligence to coordinate across eighteen separate intelligence agencies. In Britain, the old rivalries between MI5 and police counter-terrorism units dissolved into regional fusion centers and eventually into the Counter Terrorism Operations Centre in London, where MI5 officers now sit literally beside police officers and FBI agents, all working from the same room. The Five Eyes alliance—pooling intelligence between the US, UK, Canada, Australia, and New Zealand—deepened. Information sharing between Western agencies became, by any measure, infinitely better than it had been in 2001.

But better coordination has not prevented strategic disaster. In the run-up to the 2003 invasion of Iraq, MI6 allowed its intelligence to be politicized under overwhelming pressure from Washington. The agency supplied Prime Minister Tony Blair's government with assessments that Iraq possessed weapons of mass destruction. The intelligence was flawed. Iraq had possessed WMDs in the past, but they had been destroyed after the 1991 Gulf War. The Butler Review, which followed the invasion, concluded that the UK's intelligence on Iraq's alleged WMD program was seriously flawed and heavily reliant on unverified sources. General Sir Richard Shirreff, who served as a divisional commander in Iraq, later reflected: the war was based on deeply flawed intelligence, and he believed the intelligence community remained bad at learning from such failures. MI6 subsequently reorganized how it assessed raw intelligence from agents in the field, creating a clear separation between those who gathered information and those whose job was to check and challenge it.

The Security Service, MI5, faced a different kind of failure. With a database of more than 20,000 subjects of interest and numerous concurrent investigations, the agency had to make daily choices about which leads to prioritize. In 2005, it failed to prevent the 7/7 London suicide bombings, which killed 52 people. MI5 was aware of Mohammed Sidique Khan, the ringleader, but did not know what he was about to do. The Manchester Arena bombing of 2017 represented another lapse. Lord Jonathan Evans, who ran MI5 from 2007 to 2013, acknowledged that after 9/11 the assessment was clear: al-Qaeda and associated groups posed the most pressing security threat to the UK. But the picture has since changed. State threats—from Russia, Iran, their proxies, and from China—have become at least as severe a national security concern as non-state terrorism.

This shift points to a larger strategic failure. For the first twenty years of this century, Western intelligence agencies focused almost entirely on counter-terrorism and counter-insurgency. While the US, UK, and their allies fought the Taliban, ISIS, and managed the occupation of Iraq, Russia and China embarked on colossal rearmament programs. They developed hypersonic missiles and other innovations that seriously eroded NATO's military advantage. Sir Alex Younger, who was Chief of MI6 from 2014 to 2020, later acknowledged that the West missed the rise of China as a military power and as a strategic challenge. General Shirreff, in his 2016 political thriller "War With Russia," foresaw Russia's full-scale invasion of Ukraine—an invasion that would eventually occur in 2022. The West's mistake, according to Sam Olsen, Chief Analyst at the security intelligence firm Sibylline, was not simply that it was distracted by counter-terrorism. It also misunderstood the nature of China's rise, assuming that economic integration would lead to political convergence.

Today, China and Russia are top intelligence targets for MI6, yet the challenge is not primarily one of collection. Western intelligence understands a great deal about China. The problem is interpretation. Chinese power no longer lies only in ships, missiles, and troops. It increasingly lies in semiconductors, critical minerals, batteries, ports, telecommunications, and industrial capacity. The danger is that Western intelligence sees the individual pieces without always understanding what they add up to. Twenty-five years ago, on the day the planes hit, US intelligence agents had pieces of the jigsaw. They failed to fit them together and see what was coming. It remains no good to have great intelligence gathering if you cannot apply it for strategic gain.

The human cost of these failures has been substantial and ongoing. In the immediate aftermath of 9/11, swept up in fear of a second wave, the US and its allies committed numerous human rights abuses. Suspects were swept up in Afghanistan and Pakistan often on the flimsiest of tip-offs. Hundreds were flown, bound, blindfolded, and wrapped in diapers to a makeshift cage prison at Guantanamo Bay, where they were incarcerated without trial. The US still practices detention without trial there, and in 2025 deported more than 200 men to El Salvador's controversial Terrorism Confinement Centre. Britain's own stain came in 2004, when MI6 was complicit in the abduction and rendition of Abdelhakim Belhaj, a Libyan Islamist, and his wife from Thailand to Libya, where he was imprisoned and tortured by Muammar Gaddafi's regime. The case eventually came to light, resulting in a fulsome public apology delivered to Parliament by the Attorney General in 2018. Today, in-house lawyers are said to be the fastest growing department within intelligence agencies.

As artificial intelligence and quantum computing reshape the landscape, the world of intelligence and counter-terrorism continues to change almost beyond recognition. Yet the fundamental question remains unresolved: can Western intelligence agencies see the big strategic picture, or will they continue to possess the pieces without understanding what they mean? The decisions made in the years ahead—whether in response to China, Russia, or threats yet unimagined—will determine whether the lessons of 9/11 and Iraq have truly been learned.