Twenty-five years after the September 11 attacks, the security partnership between the United Kingdom and the United States remains as critical as ever, according to Britain's top diplomat in Washington. In a reflection on the anniversary, Sir Christian Turner, the British ambassador to the U.S., detailed the extensive behind-the-scenes cooperation that continues to protect citizens on both sides of the Atlantic.
Turner, who was a young diplomat preparing for his first U.S. posting in 2001, recalled the shock of the attacks and how they shaped his career. "The response to 9/11 became the backbone of my career," he wrote, noting his subsequent work against al Qaeda and the Islamic State, as well as postings in Kenya and Pakistan before arriving in Washington.
The attacks were not just an assault on America, Turner argued, but on the shared values of open, democratic societies. He quoted President George W. Bush's address to the nation, in which Bush declared that "America was targeted for attack because we're the brightest beacon for freedom and opportunity in the world."
In the immediate aftermath, NATO invoked Article Five for the first time, and British troops were among the first to deploy to Afghanistan. The conflict would claim the lives of 457 British service personnel. Turner described how the post-9/11 era transformed transatlantic security cooperation, with deeper intelligence sharing, new law enforcement partnerships, and the creation of institutions like the Department of Homeland Security and the U.K.'s Joint Terrorism Analysis Centre.
Key agreements, such as the U.K.-U.S. Data Access Agreement, have enabled timely cross-border data sharing to combat serious crime. Turner highlighted recent successes: a U.K.-led investigation into a global drug-facilitated sexual assault network brought offenders to justice in the U.S.; a planned mass-casualty terrorist attack in the U.K. was prevented using evidence from the data agreement; and convictions were secured against members of the Scattered Spider cybercrime network, linked to over 120 attacks and $115 million in ransom payments.
Looking ahead, Turner emphasized that the threat landscape has evolved dramatically. "The handrails that guided previous generations have largely disappeared," he said, pointing to hybrid threats, cyber attacks, and disinformation campaigns. He cited MI6 Chief Blaise Metreweli's warning that "the front line is everywhere."
Yet, he argued, the partnership remains a force multiplier. The U.K. and U.S. are building on the Technology Prosperity Deal to harness their trillion-dollar tech sectors, while the Five Eyes alliance continues to share intelligence and technology. Turner also noted the U.K.'s increased defense spending and the trilateral AUKUS pact with Australia, which marks its fifth anniversary this month.
As America celebrates its 250th year, Turner concluded that the lessons of 9/11 remain clear: "Freedom must be defended, security must be shared and the transatlantic alliance remains our greatest source of strength."
While the anniversary has prompted soul-searching about the unity that followed the attacks, with some analysts questioning whether such a response is now possible, Turner's message is one of continuity and commitment. The daily, unheralded work of officials on both sides continues, he said, from countering terrorist financing to dismantling scam centers and defending against cyber threats.
