A long-awaited public inquiry into Britain’s role in the Iraq war held its first hearing Tuesday, six and a half years after Tony Blair controversially led the country in backing the US-led conflict. Inquiry chairman John Chilcot, a former civil servant, said he would not shy away from criticizing the decision-making that led Britain to join the 2003 invasion despite strong opposition at home and abroad.

“What we are committed to, and what I believe the British general public can expect from us, is a guarantee to be thorough, to be impartial, to be objective and fair,” he said in opening remarks. “As I have said before, we are not a court of law nor are we an inquest nor indeed a statutory inquiry; and our processes will reflect that difference,” he added. “No-one is on trial here. We cannot determine guilt or innocence. Only a court can do that. But I make a commitment here that once we get to our final report, we will not shy away from making criticisms… where they are warranted.”

One-time top officials from the foreign and defense ministries will outline Britain’s policy towards Baghdad in the early 2000s as a five-member committee begins investigating what lessons can be learned from the US-led war. An appearance by former Prime Minister Blair, who took Britain into the conflict, is likely to be the highlight of the inquiry, although he and other Labor government figures are not due to give evidence until next year.