On the ground in Iraq, we could see mistakes unfolding one by one
Warning: Graphic content
As a battlegroup commander during the invasion of Iraq, I can say that all of the calamities that followed the ousting of Saddam Hussein were known about or feared before military action was begun. This is the key fact that the Chilcot report recognises.
It was evident on the ground, where a series of grave strategic errors unfolded. First, no attempt was made to understand what would be needed in a post-conflict Iraq and what steps should be taken to stabilise the country in its immediate aftermath. The second blunder was the disbanding of the Iraqi army and the police. On April 8, 2003, I negotiated the surrender of the Iraqi 10th Division, telling them to go home, but stressing that they would be needed in the future. Little did I suspect that the entire Iraqi army would be disbanded within weeks. This would lead to a disaster.
That decision, taken by the country's interim authority under Paul Bremmer, was completely at odds with what I understood to be the clear message that was being sent to the Iraqi army leadership prior to the conflict by our information operations.
Senior Iraqi officers were told, time and again, that if they removed Saddam or if he fell, we the West (mainly the US and UK) would seek stability through the Iraqi army and back them in running the country as the local framework for order and stability ahead of democracy and future elections.
Instead we sidelined them. This strategic blunder saw the growth, arguably, of the most effective insurgency in history since the American Revolutionary War.
In the vacuum of disorder in the British-run south of the country, various insurgent groups readily took advantage of the naive unpreparedness that characterised the response. These groups were assisted, encouraged and supplied in no small part by the regime in Iran.
And herein begins our third strategic blunder - handing the strategic advantage in the region to the Iranians.
It is barely disputed that the power behind the current Iraqi presidency is the Iranian Revolutionary Guard Corps and its charismatic leader Major General Qasim Sulaiman.
As invasion gave way to insurgency back in 2003, our troops struggled to react to the profound change in the situation around them.
When I spoke to my soldiers in my infamous eve of battle speech, I was trying to prepare them for the horrors of war. But the fury of the insurgency completely stupefied the coalition's young men and women in uniform.
In the south, the British Army went into denial, with politicos trying to spin their way out of it; they would eventually cave in and exchange militia prisoners for an end to attacks.
Further north, the US Marines responded with fury when the bodies of killed marines were mutilated. Long rows of the blackened bodies of insurgents laid out in the sun for "forensic reasons" secured an undertaking from fighters in Anbar province to stop harming the bodies of marines or even touching them.
And as Improvised Explosive Devices everywhere became more sophisticated, the penny dropped that new drills and techniques had to be delivered to aid survival in the absence of the necessary equipment. But equipment was only ever part of the puzzle. It takes time to harden young minds. Some of our soldiers were able to find a way to calm their minds on return. For some the mental scars will never heal.
Today, in Iraq, the horror continues in many grotesque forms. But it is too easy to pretend that the sectarian attacks, between Sunni and Shias, have nothing to do with the invasion of 2003.
Last weekend more than 250 people were killed by a bomb claimed by Isil. But who leads Isil?
The answer is that at its heart are former Ba'athists, led by Saddam's resourceful and cunning deputy, Lt-Gen Izzat Ibrahim Al Douri. He was the King of Clubs in the famous pack of playing cards issued by the US military before the invasion.
The regime, clearly, has not been completely changed.
Col Tim Collins was commanding officer of 1st Battalion, Royal Irish Regiment.