It looks like they were wrong about WMDs, though they did find evidence of a WMD program. And reporter Bill Gertz reported on Soviet trucks removing something (that might or might not have been WMDs) in covered trucks from Iraq to Syria.
That doesn't prove they lied. It shows they got bad intelligence. But when five or so of the top intelligence agencies in the world tell you the same thing, you're likely going to believe it.
But again, that was just one of the reasons for the war. Another, and I think this was a stronger selling point, is that some of the terrorists we were driving out of Afghanistan were being harbored in Iraq by Saddam's regime. That made Iraq another theater of the Afghan war.
Not true.- from Wikipedia concerning a dossier supplied to the US by the British govt:
“However, two sections later became the centre of fierce debate: the allegation that Iraq had sought "significant quantities of uranium from Africa", and the claim in the foreword to the document written by British prime minister Tony Blair that "The document discloses that his military planning allows for some of the WMD to be ready within 45 minutes of an order to use them."[3]
Britain's biggest selling popular daily newspaper, The Sun, subsequently carried the headline "Brits 45mins from doom",[4] while the Daily Star reported "Mad Saddam ready to attack: 45 minutes from a chemical war",[5] helping to create the impression among the British public that Iraq was a threat to Britain.
Major General Michael Laurie, one of those involved in producing the dossier wrote to the Chilcot Inquiryin 2011 saying "the purpose of the dossier was precisely to make a case for war, rather than setting out the available intelligence, and that to make the best out of sparse and inconclusive intelligence the wording was developed with care."[6] On 26 June 2011, The Observer reported on a memo from the chair of the JIC in 2003, John Scarlett, to Blair's foreign affairs adviser, released under the Freedom of Information Act, which referred to "the benefit of obscuring the fact that in terms of WMD Iraq is not that exceptional". The memo has been described as one of the most significant documents on the September dossier yet published as it is considered a proposal to mislead the public.[7]”