The key points I wish to argue are:
- The impact on public opinion of armed conflict - the use of media and the way media has been exploited, and the legalities of armed conflict.. Abu Ghraib soured the public by vexatious and false claims made by lawyers, accusations of war crimes and length of time to rebut allegations. CNN was a huge asset during the first Iraq conflict in 1990/91, where 24 hour news had just come of age. By 2002/3 it was achieving the opposite effect - the public could tune in, realtime, and check what was happening in George Bush's big brother house. Great if things are going well, you're declaring a quick victory and moving on, but not so great if its not quite going as planned. The war was unpopular from the start; people couldn't quite connect the dots to 9/11 in the way they could with Afghanistan, and the dodgy dossier and Dr Kelly affair hit the press, it gathered a negative momentum. The bizarre dismantling of the state apparatus resulted in chaos, which also kept the media fire stoked.
The pivot was on Iraq and left Afghanistan unfinished; it over-stretched HM Forces and caused two lengthy wars. The UK had good reason to be involved in Afghanistan after 9/11, Afghanistan were given the chance to hand over AQ but refused and they remember centuries old history like it was yesterday, making it very difficult to win their hearts and minds.
The overstretch was intense, particularly on pinch point units such as helicopters et al. The question you should be asking is what happened in Afghanistan whilst the focus was on Iraq; a defeated AQ/T had the time and space to regroup and rearm. Nobody can know for sure, but Afghanistan may have turned out differently if the US and UK had not taken their foot off AQ/T's throat at such a critical time.- The British government failed to tackle Islamic radicalisation of its youth, many young people were radicalised in prison because radical preachers preyed on the so-called "underclass," the likely bogus claims about the Iraq War allowed AQ to brainwash misguided young Muslims in to believing that their own Government hated them and terrorism was the only way to gain respect and live a prestigious life. Yes and no..... you are right that this period saw an uptick in home grown terrorism, but I don't believe the cause was just Iraq... a big aspect, yes, but bear in mind Afghanistan and lots of other operations were being conducted around the world. I'd lean towards Iraq being the major aspect of radicalisation, but not the only aspect.
And finally (if there's space), I will attempt to argue that the British public have less contact with the military, less trust in their use for what they see as "legitimate" purposes, which directly aids terrorism as they cease to support adequate funding due to being less "militaristic" and aware of the current threat, due to a reduction in national pride and patriotism after the chaos they see to have been caused in Iraq.
I would make space..... up to 1989/1990, the public saw cold war defences as a major issue (Labour lost the 1987 election mainly over defence). The 1991 gulf war was fairly clear cut - Iraq had invaded a neighbour. Then followed a procession of small intervention wars - Bosnia, Kosovo, Sierra Leone which were fairly clear in aim and purpose (stand fast the ROE and UN involvement in Bosnia) and winnable. Then came 9/11.... people initially saw the logic in Afghanistan - but for some reason I can't fathom, the government never mentioned Article 5 of the NATO treaty, and gave all sorts of reasons for military involvement - drugs, womens rights etc etc with the net effect of distorting the purpose and objective - the public then expected results that the government could not deliver, and as the casualty rate climbed, what was a fairly good cause became mired in failure. Iraq was different; the purpose was unclear from day 1, and the government had little support from the moment the first member of the armed forces set foot on Iraqi soil (or sand). The result, as you point out, was chaos and has soured the public's view of military operations since (quite justifiably) - however, and this is important, Iraq could have easily become a Vietnam, but no matter how unpopular the war became, the public made the distinction between soldiers doing what they were told, and an ill conceived foreign policy disaster - the war was unpopular, but I don't feel public attitudes towards the military shifted greatly.