By ANDREW BUNCOMBE In Washington
The head of the CIA says it will be at least five years before the United States develops the intelligence capabilities to take on terrorists such as al Qaeda.
George Tenet also admits his agents flatly failed to penetrate the September 11 plot.
Tenet, whose agency was criticised by the independent commission investigating the 2001 attacks on New York and Washington, said he and his colleagues had failed those people who died in the strikes.
"We all understood [Osama] bin Laden's attempt to strike the homeland. We never translated this knowledge into an effective defence of the country," he testified before the commission yesterday.
"No matter how hard we worked, or how desperately we tried, it was not enough.
"The victims and the families of September 11 deserved better."
The failures outlined by the commission - which issues reports before testimony is given - and admitted by Tenet were not failures of effort or intention.
Rather, a picture emerged of an intelligence community still grounded in the challenges of the Cold War and ill-prepared to deal with the threat presented by stateless terrorists using unconventional means of attack.
"With the important exception of attacks with chemical, biological, radiological or nuclear weapons, the methods developed for decades to warn of surprise attacks were not applied to the problem of warning against terrorist attacks," said the commission's report.
"Most [importantly], our interviews with policymakers in [the Clinton and Bush] Administrations revealed a fundamental uncertainty about how to regard the threat posed by bin Laden and al Qaeda.
"After September 11, the catastrophic character of the threat seems obvious. It is hard now to recapture the old conventional wisdom before September 11."
Tenet, the senior intelligence official in the US and the man who usually provides President George W. Bush with his daily intelligence briefing, said changes were being made but it would be another five years before America had "the kind of clandestine service our country needs".
Staff statements and testimony from yesterday's session of the 10th hearing of the National Commission on Terrorist Attacks Upon the United States (the 9-11 Commission):