25 years after 9/11, America and Britain still stand stronger together

Twenty five years ago, I was a young British diplomat preparing for my first posting to the U.S. Like millions across the United Kingdom and around the world, I will never forget the horror of watching the bright blue skies of America darkened by an act of terror that claimed thousands of innocent lives.

The response to 9/11 became the backbone of my career, with my professional life shaped by the responsibility to protect our people. That journey has taken me from work at the heart of U.K. government in the fight against al Qaeda and the Islamic State to leading British missions in Kenya, Pakistan and now the U.S..

For the U.K., the attacks represented more than an assault on our closest ally. It was an attack on the values at the core of our open, tolerant democratic societies.

Addressing the nation that evening, President George W. Bush spoke for all of us: “America was targeted for attack because we’re the brightest beacon for freedom and opportunity in the world. And no one will keep that light from shining.”

The following day, NATO invoked Article Five for the first time, affirming that an attack on one member was an attack on all. British forces were among the first to deploy alongside American troops in Afghanistan. In the years that followed, 457 British service personnel made the ultimate sacrifice and never came home from that mission.

When I arrived in Washington in 2002, I witnessed how profoundly the post-9/11 era transformed transatlantic security cooperation on a scale not previously seen. Our intelligence agencies deepened information sharing. Law enforcement teams forged new partnerships. Together, Britain and the U.S. strengthened border security, enhanced aviation protection and expanded sanctions regimes.

Institutions such as the Department of Homeland Security and the U.K. Joint Terrorism Analysis Centre became central pillars of a new security architecture, bringing together intelligence and operational coordination.

The U.K.-U.S. Data Access Agreement gave authorities on both sides of the Atlantic timely and lawful cross-border access to critical data needed to prevent the most serious crimes.

Yet, as I reflect on the past quarter century, I am struck by how much the threat landscape has changed. The handrails that guided previous generations have largely disappeared.

Today, we face a world of hybrid threats, geopolitical instability and rapid technological change. Hostile state and non-state actors, cyber attacks and disinformation campaigns increasingly blur the line between peace and conflict. In her first public speech as Chief of MI6, Blaise Metreweli warned that the “front line is everywhere.” She is right.

But one constant endures: when the U.K. and the U.S. confront these challenges together as a true team of teams, we are stronger and safer than either of us could ever be alone.

That security partnership delivers real-world results every day. In the last year alone, U.K.-led investigations into a global network which drugged victims to facilitate sexual assault helped bring multiple offenders to justice in the U.S. and safeguard numerous Americans.

Our teams prevented a planned mass-casualty terrorism attack in the U.K. The successful prosecution relied on evidence obtained through the U.K.-U.S. Data Access Agreement.

Working together, the U.K. convicted key members of the Scattered Spider cybercrime network, one of whom the U.S. has linked to more than 120 attacks and $115 million in ransom payments.

This summer, our teams worked side by side to help protect fans and players at the FIFA World Cup, with a focus on preventing drone attacks.

Away from the headlines, British and American officials work together every single day to combat terrorist financing, dismantle scam-center fraud and tackle cybercrime. We continue to conduct military operations to disrupt terrorist activity.

Looking ahead, we have an opportunity not merely to respond to threats, but to stay ahead of them as force multipliers.

Building on the U.K.-U.S. Technology Prosperity Deal, we have a golden opportunity to harness the combined strengths of our trillion-dollar technology sectors and out innovate those who would challenge our security and prosperity.

The Five Eyes partnership remains at the cutting edge of intelligence and technology sharing to help stop threats before they unfold.

NATO defends the North Atlantic, the US eastern seaboard, and the High North, while extending U.S. reach through the combined strength of its Allies. The UK is already NATO’s third-highest defence spender in cash terms and has committed an additional $20 billion in funding to a defence plan that’s set to spend $393 billion over the next four years.

Meanwhile, our trilateral AUKUS partnership with Australia represents another important step forward. As it approaches its fifth anniversary this month, it stands as a generational investment in deterrence and technological warfighting cooperation.

Among the nearly 3,000 people murdered on Sept. 11, 2001 were citizens from many backgrounds and faiths, including 67 Britons. Today, we remember them all: the victims, the first responders, the medical personnel and the servicemen and women who gave so much.

As America celebrates its 250th year, the lesson of 9/11 remains as relevant as ever. Freedom must be defended, security must be shared and the transatlantic alliance remains our greatest source of strength.

Sir Christian Turner is the British ambassador to the U.S .