The mission in Afghanistan “remains difficult” say David Cameron and Barack Obama in a joint article today in the Washington Post, a conclusion that errs on the side of understatement.

After a week in which the UK lost six soldiers in a single IED attack and a US soldier on a murderous rampage killed 16 Afghan civilians, the aim of the two leaders appears to be to bail out as fast as possible - but “in a responsible way” as President Obama put it.

The flurry of deaths in the past week will sharpen the two leaders’ concentration on that task as they meet in Washington. Only four out of 595 fatal IED incidents between 18 May 2009 and 22 January 2012 had claimed six lives or more among International Security Assistance Force personnel, and so last week’s loss in an attack on a Warrior armoured personnel carrier in the border area between Helmand and Kandahar is unusual as well as tragic. The mean number of deaths in a fatal IED attack has been steady at 1.4 since 18 May 2009.

Recent trends in military casualties have, in fact, been reasonably good. Our latest report (Bird and Fairweather, 1 February 2012, accessible here) on military fatalities in Afghanistan by nationality and cause during the 20 weeks of Period 15 (5 September 2011 to 22 January 2012) attracted little attention for that reason: the UK military fatality rate was much reduced in 2011. 

However, we drew attention yet again in that report to the failure to produce any comparable figures on the fatality rates experienced by ISAF-trained Afghan National Army personnel who will take over when US, UK and other ISAF troops withdraw.

The summary below (see Table) provides a year-by-year count of UK military fatalities, combined with a mid-year estimate of the number deployed, which enables the rate of casualties to be calculated. Our resume lacks detail on when troop numbers escalated and it does not differentiate, as our more detailed analyses do, between the "fighting season" and the Afghan winter.

However, it is sufficient to convey some key features:

1. 2011 is the first of the past six calendar years in Afghanistan when UK troops have faced less than major combat (which we define operationally as six fatalities per 1,000 personnel-years) and 
2. 2009 and 2010 exacted a very heavy toll indeed.

Given the responsibility that will shortly fall on the Afghan National Army, it would be appropriate to include a second table showing how much of the burden in terms of casualties it has been taking. But such a table would be empty because the UK and other ISAF-country governments have seemingly made insufficient effort either to record and disseminate this information themselves or to persuade the Afghan government, as a matter of international public accountability, to develop the capability of so doing.

All the table would contain is a single number – 184,000 – the count of those trained by mid-2011, according to an answer given in the House of Commons by Mr Cameron on 7 March. The gaps in knowledge are unacceptable. While UK troops serve in Afghanistan alongside ISAF-trained ANA troops, there is an obligation on the UK government to know, and to publish, the level of combat that ISAF-trained ANA forces encounter, and how their fatality-rate compares with that of troops from ISAF-nations, such as the UK.

The obligation is strengthened because, in the 60 weeks of Periods 13+14+15 (29 November 2010 to 22 January 2012), when there were 638 ISAF-fatalities in Afghanistan, treachery by Afghan personnel or trainees claimed at least 29 of them, all by small arms fire, and so caused 4.5 per cent of all deaths and 24 per cent of the deaths caused by small arms fire.