In the war logs they are labelled simply "green on green". But "green" is the military's jargon for Afghan or "host nation" armed forces, and the accounts of more than 50 incidents where local troops opened fire on their comrades paint a vivid picture of the lawless quality of life in the country.

British troops from 1st Battalion The Rifles filed a report from Garmsir in Helmand province on 11 April 2009 about the behaviour of local militia at their base.

The border guards on the roof were "high on opium and having a party", they said. The racket woke up some sleeping "terps" (interpreters) below and a fight ensued.

The British commanding officer tried to mediate but when shooting started an alarmed British sentry also fired a shot "believing the lives of his … commander and platoon sergeant were in danger". A bullet hit one of the quarrelling border guards in the stomach and killed him. The report went on to claim it was unclear who fired the fatal shot.

The border guards, considered often as a poorly disciplined local militia, figure in several of these violent disputes.

At Delaram in adjoining Nimruz province, commuters on the country's main highway complained to US authorities in January 2007 that border guards were extorting money and goods at checkpoints. They were reported to have stolen $2,000 from one man.

Eventually there was a shoot-out with the border guards at local police headquarters, which came under siege. Three guards were killed and two police wounded. Nor was that the end of it – the US army reported: "The police support team expects retaliation."

Local police are also accused of bribery. In April 2008 it was reported that a group of Afghan army troops "observed a ... police officer taking money from a civilian truck driver ... So they attacked and beat the [police] officer. A firefight ensued."

That melee led to the wounding of two soldiers and the locking up of all the police in the local jail.

Bad blood between police and soldiers appears commonplace. In September 2007 a police trooper hit an army officer with the door of his car in a local bazaar. In the ensuing fracas soldiers managed to shoot three innocent passers-by.

The war logs add: "Analyst comment: this will damage the populace's view of the [government] in Mehtar Lam and significantly aid the insurgency … Tempers were likely high due to Ramadan fasting."