The Hutton report did not say that. If it had accused the Blair government of actually lying, then it would have fallen.
They can legitimately be accused of "sexing up" the dossier, in that they didn't put something like 'the UK has some evidence (which it has so far been impossible to verify) that suggests Iraq has chemical weapons it can deploy at 45 minutes' notice'. They didn't do that, or from memory caveat the phrase much at all - rather they said that UK intelligence indicated that Iraq had WMD that could be deployed at 45 minutes' notice.
This was a relatively un-controversial matter at the time in a report that didn't really say anything all that interesting. I read that dossier, and it basically pointed out all the stuff that we knew Iraq had got, because the UN had tracked its existence in the 90s, but not managed to destroy it before the weapons inspectors were finally kicked out.
It also pointed out that Iraq still had the scientists and information to reconstruct their WMD programs as soon as sanctions were removed, which was definitely true. And that they were still in violation of the UNSC resolutions because they were still keeping SCUD missiles, which they later used.
So the Hutton report was quite damning because of the all the criticism of process and sofa government. It accused them of stripping the qualifying language out of the report, not lying. There's a massive difference.
The question wasn't do we think Iraq has WMD, as almost everyone believed that to be true. Even if not, once they had the cash they still had the scientists and the knowhow - so in intelligence terms they retained the capability. The question was did they have useable WMD? If so, was it actually deployable?
That was much more controversial, because apart from the SCUDs and the mustard gas, the Iraqis were pretty shit at WMD. They weren't all that hot at getting the purity high enough in their nerve agents, which meant they couldn't store them very long, and their biological program was a pretty big failure. As was the nuclear program. They also failed to get a chemical delivery system that fitted on a SCUD, and I seem to remember their air-dropped munitions were pretty shit as well. What they had lots of was mustard gas shells. Which I guess is why the Iran-Iraq war was basically WWI with extra sand.
But you can't accuse Blair of lying - because by definition a lie is someobody saying something that they know to be false. And all the evidence and enquiries point to Blair, the government and the intel community believing that Iraq had WMDs - there was no good reason to think otherwise, given the information availeble. The only question was whether they were actually useable - let alone deployable.
Groupthink, spin, poor decision making processes and planning are the accusations the various reports level. They're bad enough. You don't have to make the shit up about lying, which is transparently untrue. That loses you any chance at the moral high ground.