A very short Chatham House briefing paper (less than 30 pgs) and IMHO sits here: Depending on the Right People: British Political-Military Relations, 2001–10. The summary starts with:
There is a widespread view that Britain’s politicians should bear the main blame for the country’s military difficulties in Iraq and Afghanistan. In particular, they are accused of failing to heed professional military advice and of launching over-ambitious missions with insufficient resources. Recent evidence, including from the Iraq Inquiry, shows that this view is too simplistic.
Instead, Britain seems to have suffered a wider failure of the government system, with politicians, senior military officers and civil servants all playing their part.
Link:http://www.chathamhouse.org/sites/de...deWaal1113.pdf

For reasons lost on me the author, a UK diplomat on study leave, remarks:
Britain must learn from US experience and from its own mistakes.
Another article to read one day.