I think part of the issue also lies in the very confused chain of command which existed between the UK in Basra and the US in Baghdad. While technically under Baghdad control, IMHO the UK played its cards as though MND(SE) was under direct UK control and not part of an overall Coalition. Link to this the lack of clear direction from the UK and the situation is set for all sorts of horrors!

From a UK perspective: Confused Chain of Command, lack of resources, strategic drift instead of direction (the only direction appeared to be 'don't rock the boat' and 'don't incur casualties') and (IMHO) an overwhelming sense at the time that 'we must be great at COIN after 25 years in N Ireland - so we needn't apply ourselves to this spot of bother'... and the scene is set!