Sir John Chilcot has said he does not believe Tony Blair was "straight with the nation" about his decisions in the run-up to the Iraq War.
The chairman of the public inquiry into the 2003 conflict said the former prime minister had been "emotionally truthful" in his account of events leading up to the war.
In an interview with the BBC Sir John was then asked if Mr Blair was as truthful with him and the public as he should have been during the seven-year inquiry.
He replied: "Can I slightly reword that to say I think any prime minister taking a country into war has got to be straight with the nation and carry it, so far as possible, with him or her.
"I don't believe that was the case in the Iraq instance."
A spokesman for Mr Blair told the BBC that "all these issues" had been dealt with.