The Chilcot Report is not the first document on the Iraq war. Before there were two reports, prepared by parliamentary committees, and also Butler and Hutton reports. So this is the fifth report.
In principle, almost all aspects of the case are clear. The consequences of the war in Iraq, the whole situation, when Prime Minister Blair, to say it mildly, misled the parliament, were already known.
One of these effects was the vote of the British Parliament in August 2013 against the use of military force in Syria. By the time it was already known that the intelligence data were specially "fitted" and therefore parliamentarians, despite the Prime Minister Cameron's pressure, voted against the invasion in Syria. Due to the fact that the British Parliament voted against, the United States decided not to use force alone.
The second consequence may not seem so important, but sufficient for solving procedural issues in the UK. Firstly, Gordon Brown, when he was prime minister, tried to transfer the right to declare war and peace from the monarch to the parliament, but this did not happen. However, the use of armed forces abroad can not be a sole solution only by the government, the question should be put to the vote of parliament. The parliament's decision is not binding, but politically it is impossible to overcome. The same situation is with the outcome of a referendum on Britain's exit from the EU. The referendum was not legally binding, but politically it is impossible to deny the result.
As for the Labour Party, Jeremy Corbyn from the beginning was against the war in Iraq and calls it a disaster. He has already apologized to the families of dead British soldiers. As for Tony Blair, there is no such procedure to punish him. The International Criminal Court has just said that it can investigate the military crimes, but it can not make judgments about the decisions to declare war and military intervention.
British MPs propose to impeach Blair. This solution simply will not allow Blair to continue to hold public office. All this, of course, will have symbolic character, because already no one will give Blair any post in view of the fact that he is completely discredited. And not just because of "fitted" intelligence data, but also by the fact that in July 2002 he promised Bush full support, no matter what happens.
Let's not forget that the invasion of Iraq was illegal, without the UN Security Council resolution. Tony Blair tried to get such a resolution, but it did not work, because not only Russia was against it, but also France.