Lord Prescott has said he had doubts about intelligence on Saddam Hussein's weapons programmes before the 2003 invasion of Iraq.
The ongoing inquiry has heard from the former deputy prime minister who dismissed some of the UK spy agencies' information about the Iraqi threat as "tittle tattle."
He has also described the intelligence about supposed weapons of mass destruction as "not very substantial".
Lord Prescott said conclusions in reports on Iraq prepared by the Joint Intelligence Committee (JIC) went beyond the evidence available.
He noted that the 2004 Butler Inquiry found the recommendations made to Ministers on the basis of pre-war intelligence about Iraq were "frankly wrong".
Lord Prescott also said he felt "nervous" about the notorious claim published in the Government's September 2002 dossier that Saddam could launch WMD within 45 minutes.
Referring to the JIC reports on Iraq, he told the inquiry: "When I kept reading them, I kept thinking to myself, 'Is this intelligence?'
"It's basically what you have heard somewhere and what somebody else has told somebody. Presumably that's how intelligence is brought about.
"So I got the feeling it wasn't very substantial, but it clearly was robust.
"As we knew more and more whether there was evidence of Iraq involved in weapons of mass destruction, the conclusions were a little ahead, I think, of what the evidence we had. Perhaps that's the way it is."