Outraged politicians jumped on the revelation to accuse Blair of misleading the public and said it cast doubt on the credibility of his whole case against Saddam.
"This is the sort of thing that Saddam Hussein himself issues," fumed opposition Liberal Democrat Jenny Tonge.
One of Blair's former junior defence ministers, Peter Kilfoyle, said he was shocked that the government was trying to win over Britons on such "thin evidence".
Sections in the dossier on Saddam's security apparatus drew heavily on a 2002 article written by Ibrahim al-Marashi, a 29-year-old US postgraduate student of Iraqi descent who works at California's Monterey Institute of International Studies.
His major sources were captured Iraqi intelligence documents from prior to 1991 that are part of Harvard's Iraq Research and Documentation Project, as well as books and public information.
Marashi, who has never been to Iraq, told Reuters he was surprised and flattered that his research ended up in a British government dossier -- but could have provided the government with updated information if anyone had asked.
"The fact that they would have to turn to something in the open media reflects that maybe there is a deficiency in the intelligence gathering," he said.
"My primary worry at the moment is that it might reflect poorly on Powell's presentation by the very fact that he referred to that document."
Glen Rangwala, an Iraq specialist at Cambridge University who analysed the Downing Street dossier, told Reuters 11 of its 19 pages were "taken wholesale from academic papers".
"If the nature of the intelligence is actually just web research, then it rather casts doubt about the plausibility of the government's earlier claims," said Rangwala.
The editor of Jane's Intelligence Review, Chris Aaron, said sections of articles in his magazine published between 1997 and 2002 were also used in the dossier.
"The fact that the UK dossier does not identify the source for each bit of evidence in the report could be taken as misleading or taken to be an effort to disguise the classified material included in the dossier," he said in a statement.
The dossier was released as Britain pours tens of thousands of troops into the Gulf to support US preparations for possible military conflict with Iraq.
Ministers have privately admitted that gathering information on Iraq is difficult and intelligence on Baghdad is "thin".
Blair's spokesman insisted the document was fundamentally accurate, and said no one could dispute its central argument that Iraq was trying to deceive the UN inspectors.
"In retrospect, we should, to clear up any confusion, have acknowledged which bits came from public sources and which bits came from other sources," he said.
The UK dossier:
Iraq – its infrastructure of concealment, deception and intimidation
Ibrahim al-Marashi:
Iraq's security and intelligence network: a guide and analysis
Published in the Middle East Review of International Affairs, Sept 2002
Herald feature:
Iraq
Iraq links and resources
