The long-awaited Chilcot Report is the result of a seven-year inquiry into Britain's role in the 2003 Iraq War, which led to the downfall of Saddam Hussein.
Made up of 12 volumes and 2.6 million words, what exactly is it? And why should you care?
Who is Chilcot?
The report is named after the inquiry's chairperson and former civil servant Sir John Chilcot.
It looks at why certain decisions were made back then by people like former British Prime Minister Tony Blair, and asks how future responses to perceived global threats could be improved
What did the report actually find?
The report made for unpleasant reading for Mr Blair:
However, Sir Chilcot says the chaos in Iraq which followed the invasion should have been foreseen. "UK planning and preparation for the post-conflict phase of operations, which rested on the assumption that the UK would be able quickly to reduce its military presence in Iraq and deploy only a minimal number of civilians, were wholly inadequate," he said.
So after seven years of waiting for the report, what does Mr Blair have to say for himself?
He acknowledges mistakes were made and says he has "more regret than anyone will ever know".
Yet despite the evidence of wrongdoing, he says he'd do it again.
"I think people want me to go one step further," he says. "And this my problem... They say 'no we want you to apologise for the decision'... I can't do that."
So where does New Zealand come into all of this? What was our position at the time of the war?
Then-Prime Minister Helen Clark officially condemned the invasion, despite having a strong relationship with the US and Britain.
However, we did eventually send personnel to undertake humanitarian and construction work.
There were 179 British soldiers killed in the Iraqi invasion and criticism from their families has been swift.
Sarah O'Connor's brother Bob O'Connor was killed when the plane he was travelling in was shot down near Baghdad.
"There is one terrorist in this world that the world needs to be aware of, and his name is Tony Blair… the world's worst terrorist," she says.
The families could now launch a civil suit against Mr Blair.
Thirteen years after the invasion, the region remains as unstable as ever, thanks to the terrorist groups which filled the void left by Saddam Hussein.