In the action at Hillah in Iraq on 24th July 1920, over 180 British and Indian Army troops lost their lives, many having being executed after being taken prisoner. The main British Regiment involved was The Manchester Regiment, who bore the brunt of the casualties. This was one of the biggest losses of life ever suffered by the British Army in a single day outside of a major war.
In an unattributed article on a website called
The Soldiers Burden I found the following quote:
Sadly the British Army commanders in the recent invasion of Iraq appeared unfamiliar with the 1920 campaign. If those commanders had disseminated the lessons of that campaign to their subordinates, then perhaps more understanding of the situation would have been apparent, resulting in less British body bags being transported to the rear and in less suffering being inflicted on the local population. Such a study would have been a fitting tribute to the British soldiers and their adversaries who fought and died in the country in 1920.
I make no comment on tactics employed either in 1920 or 2002 onwards, I am not qualified to do so, but modifying the above quote to say that if politicians had learned the folly of getting involved in Iraq (and indeed Afghanistan), then the 680 lives referred to by CGB would have been saved.