A highly critical report due to be released later this week by the Senate select committee on intelligence is expected to lambast the intelligence community for doing a poor job of collecting information about Iraqi weapons programmes and for failing to pass on what information it did have.

The committee is expected to single out the outgoing CIA director, George Tenet, and his deputy, John McLaughlin, for particular criticism, according to the New York Times. It found no evidence that the CIA made these mistakes because of political pressure from the White House or the department of defence.

Mr Tenet has recently been interviewed privately by the panel, which asked him whether he had told Mr Bush that the case that Iraq had weapons of mass destruction was a "slam dunk", as reported in Bob Woodward's book Plan of Attack. Mr Tenet reportedly refused to confirm or deny using the phrase, saying that his conversations with the president were privileged.

The report reveals that relatives of Iraqi scientists told the CIA that Saddam had abandoned attempts to develop unconventional weapons, but the CIA failed pass these statements on to Mr Bush, even as he made public claims to the contrary. One CIA spokesman told the New York Times that the families' statements were ignored because they were "not at all convincing".

The committee found that one Iraqi defector, whose testimony had been used as evidence of a biological weapons programme, had actually said he had no knowledge of it. They did not unearth the contradiction until they read original reports of his debriefings before the war.