Sir John Chilcot has delivered his scathing report on the Iraq War.
Here are the six key things we learned:
UK joined invasion 'before peaceful options had been exhausted'
Tony Blair ordered the invasion of Iraq before "peaceful options for disarmament had been exhausted", and at a time when Saddam Hussein posed "no imminent threat".
"Military action at that time was not a last resort," Sir John concluded.
Blair wrote to Bush
Nine months before the invasion in July 2002, Blair wrote to US President George W Bush to say: "I will be with you through whatever".
But there was no support for Blair critics' claim that he agreed a deal "signed in blood" to topple Saddam with Bush in April 2002.
Tony Blair is also said to have "overestimated his ability to influence US decisions on Iraq".
Intelligence on Iraq was flawed
The decision to go to war was based on "flawed intelligence" that should have been challenged, the report said.
Prime Minister Tony Blair's September 2002 Commons statement and dossier on Iraq's weapons of mass destruction (WMDs) was also judged to have been "presented with a certainty that was not justified".
Decision on legal basis for war was taken in 'unsatisfactory' manner
Attorney General Lord Goldsmith's decision that there was a legal basis for UK involvement in the war was taken in a way which was "far from satisfactory".
British troops were put at risk
The Ministry of Defence was accused of being too slow to respond to the threat of Improvised Explosive Devices (IEDs) to troops.
Delays in providing better-protected patrol vehicles "should not have been tolerated", the report also said.
Sir John Chilcot claimed it was "humiliating" that by 2007 British troops in Basra had to use prisoner exchanges to get militias to stop targeting them.
Post-war planning was inadequate
The report was scathing in the government's failure to adequately prepare and plan for a post-conflict Iraq without Saddam Hussein.
Explicit warnings about civil war, Iranian influences and al-Qaeda made before the invasion were ignored.