Almost seven years since it was first launched, the Iraq inquiry - also known as the Chilcot inquiry - has been published, looking into the events that led up to Britain's invasion of Iraq in 2003.
The decision to go to war in Iraq and remove Saddam Hussein from power was made by then-prime minister Tony Blair in a coalition of 40 countries - and led to the deaths of 179 British troops.
An inquiry into the decision, which cost £10 million to produce and involved scrutinising around 150,000 Government documents, began six years later and the report was released on Wednesday.
Tony Blair gave a statement, in which he said he accepts "full responsibility" for the decision.
And as MPs begin the task of debating the outcomes, here are the facts you need to know about what has happened during the inquiry in the 2,578 days since it was opened...
July 30, 2009: Sir John Chilcot officially launches the inquiry, saying he will hold as many public meetings as possible and the panel "will not shy away from making criticism" if it finds that mistakes have been made.
January 18, 2010: Jonathan Powell, chief of staff to the prime minister, denies there was any attempt to "bully" attorney general Lord Goldsmith into authorising the war.
January 19, 2010: Former defence secretary Geoff Hoon says the Treasury, under Gordon Brown as chancellor, failed to fund the forces properly in the years before the conflict and then slashed their budget following the invasion.
January 21, 2010: Former Foreign Secretary Jack Straw, admits he only "very reluctantly" supported the invasion of Iraq.
January 27, 2010: Lords Goldsmith gives evidence and says he gave the "green light" to invade Iraq just two days after meeting US government lawyers.
January 29, 2010: Blair defiantly tells the inquiry that he has no regrets over removing Saddam Hussein and would do the same again.
July 30, 2010: Sir John Prescott discloses that he had private doubts about the intelligence used to justify the 2003 invasion of Iraq.
January 21, 2011: Blair is jeered and heckled by relatives in the hearing room as he said he "deeply and profoundly" regretted the loss of life in the Iraq war.
January 27, 2011: Lord Boyce, former chief of defence staff between 2001 and 2003, tells the inquiry that Blair repeatedly failed to deliver on his promises to provide the military with all the resources they needed for operations in Iraq.
February 2, 2011: At the last public hearing, Jack Straw says that he told Blair just days before the Iraq invasion of Iraq that British troops did not necessarily need to be sent with the Americans.
February 4, 2015: After months of fiercely criticised delays, Sir John himself faces a grilling by the Commons Foreign Affairs Committee, but says that the task of providing those most deeply affected by the Iraq war with "the answers they deserve" must not be rushed.
July 6, 2016: The inquiry committee intends to publish the Report of the Iraq Inquiry, including all but the most sensitive information which could threaten national security.