Sir Jeremy Greenstock was British Ambassador to the UN until the Iraq war and Special Envoy for Iraq after the war.
So he was well placed to write his book, Iraq: The Cost of War, which was held back from publication for 12 years and finally published after the Chilcott Report.
His main conclusion was that the peace after the Iraq war was mismanaged and ensuring the stability of Iraq was not prioritised by the US or the UK. His observations on diplomacy, politics and human nature were many and varied.
I am not sure I agree with all of them but it was an interesting talk which he gave at Buxton International Festival.