Karzai's argument that the UK troop increase in Helmand in 2006 created today's insecurity will sting politicians, but what he says is true. I remember the events clearly; I was in Afghanistan at the time.
Prior to 2006 there was no insurgency of note in southern Afghanistan and sporadic fighting in other parts of the country. The model being used was what Conservative minister Rory Stewart - who has spent time considerable in the country - refers to as the light footprint; few troops, a less aggressive posture and a softly-softly approach. The motivations behind the initial invasion are contested - I consider the war wholly avoidable - but it has to be said that this careful approach to occupation was paying off.
The decision to re-focus on Afghanistan was, in my view, partly driven by hubris: Iraq was a failure and the West needed a success story. I was among the first detachment of soldiers from the 16 Air Assault Brigade battle group to reach the country in early 2006. Thereafter, the south of the country was flooded with troops and it was this increased presence that sparked the insurgency we see today.
Apologists for what has happened since tend to use a stock argument that the insurgents are the ones doing the killing and causing instability. This may be the case, but we should be absolutely clear: the insurgency was itself created by the occupation. It's also important to step away from cross-party ideological spin about 'staying the course' because 'our lads have died for us' - this is merely an attempt to justify the next dead or maimed soldier by talking about the last one. This isn't about ideology; this is about chronology.
Before 2006 there was little insurgent activity of note. After 2006 a profound insurgency had developed. What had changed? The number of troops and a new marauding posture dreamed up not by soldiers, but by politicians. The deaths of over 400 UK soldiers and an unknown number of Afghans in this newer, higher tempo war were authored in Downing Street.
The decision, made to regain some kind of political capital from the disaster in Iraq, has merely created another disaster in Afghanistan. Here's an anecdotal example: when I arrived in southern Afghanistan ahead of the main body of soldiers to organize ammunition, the demand for bullets and bombs was low - a few boxes of small-arms rounds here and there. The escalation of violence as troop number increased was such that a few months later so many high explosive 105mm artillery shells were being fired that the theatre stocks simply ran out.
The rates of attrition and casualties soared as the light footprint was replaced with the pounding of boots. Amongst the range of confused headings which were given to the post-2006 effort in Helmand, the claim that troops were there 'peacekeeping' has to be examined in this light. Genuine peacekeeping forces do not traditionally fire so much artillery that they run out of ammunition.
The choice to re-invade Afghanistan in 2006 has proven to be the mother of all bad decisions. It gifted the Taliban and other insurgent elements the role of liberators; we created the support for our own demise among the population.
Karzai is right on this, the insecurity in southern Afghanistan is not home-grown. It was imported by us.
The Huffington Post UK with Goldsmiths, University of London event 'The Great Iraq War Debate: Was It Worth It? Iraq, Ten Years On' takes place on 7 February 18:30 - 21:00 (19:00 start)
Venue: Great Hall, Richard Hoggart Building, Goldsmiths, University of London, SE14 6NW
Price: Free, but reserve your place at www.amiando.com/iraqdebate