The families have been incensed by claims from people who have seen the blanked-out section that it describes how senior Saudi officials distributed hundreds of millions of dollars to charitable groups and other organisations that may have helped to finance the attacks.

A formidable group known as the Jersey Girls, consisting largely of widows and orphaned children from New Jersey, will meet today to discuss how to see the censored pages.

The New York Times reported yesterday that sources who had seen them said they showed how, under the guise of support for Islamic charities, Saudi Arabia’s ruling elite distributed millions of dollars to terrorists.

Kristen Breitweiser, a leading advocate of full disclosure of the congressional hearings, said that the litany of intelligence lapses exposed by the inquiry was disgusting, but the omission of evidence from the 858-page report for political reasons was worse.

Breitweiser, who lost her husband Ronald in the World Trade Center, said she felt sick when she read the report. “Maybe the real answers as to whether the attack could have been prevented are in the censored chapter,” she said. “ If we have to go to court to get all the answers, we shall.”

Deena Burnett, 38, whose husband Tom helped to lead the attack on the hijackers on flight 93, which crashed in Pennsylvania, said: “We’re getting more co-operation from Spain, France and Germany than from our own country.”

Her criticisms were echoed by Ron Motley, a lawyer whose firm, acting on behalf of Burnett and 600 bereaved families, is suing members of the Saudi royal family for allegedly providing financial backing to Al-Qaeda.

“We are going to appeal to Congress to release the whole thing,” said Motley. “There is no security argument that can justify leaving out these pages.”

The publicly available elements of the report reveal a pattern of poor communication between rival intelligence agencies and a failure to grasp the significance of clues.

It confirmed speculation that the “best chance to unravel the September 11 plot” was lost when the CIA failed to tell the FBI that two men living in the same house in California before the attack were suspected Al-Qaeda terrorists. The men, Khalid Almidhar and Nawaf Alhazmi, went on to crash one of the four hijacked airliners into the Pentagon.

Prince Bandar bin Sultan, the Saudi ambassador to the US, has condemned as “outrageous” claims that his country was failing to co-operate in fighting terror and had helped to fund the hijackers.

“The idea that the Saudi government funded, organised or even knew about September 11 is malicious and blatantly false,” he said. “In a 900-page report 28 blanked-out pages are being used by some to malign our country.”

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