A culture of drug-taking and "indiscipline" exists among Afghan nationals working with British troops in Afghanistan, a preliminary inquest hearing into the deaths of five British soldiers has been told.
The UK troops were murdered by an Afghan policeman on November 3 2009.
The soldiers were gunned down without warning by an officer they had been living alongside at an Afghan National Police (ANP) checkpoint in Nad-e-Ali in Helmand Province.
Warrant Officer Class 1 Darren Chant, 40, Sergeant Matthew Telford, 37, and Guardsman Jimmy Major, 18, from the Grenadier Guards, died alongside Corporal Steven Boote, 22, and Corporal Nicholas Webster-Smith, 24, from the Royal Military Police.
They had just returned from a patrol and had taken off their body armour and were drinking tea with their Afghan colleagues in the courtyard of the compound.
The suspect, named only as Gulbuddin, suddenly opened fire from the roof of the checkpoint with a machine gun before anyone could respond, then fled.
The Taliban claimed responsibility for the murders and some reports suggested Gulbuddin had escaped back to them, but military sources have previously suggested the attack was probably unconnected to the insurgents.
Another six British soldiers and two Afghan policemen were wounded in the attack at Checkpoint Blue 25.
The preliminary hearing, held at Trowbridge, Wiltshire, was told that the taking of opium and cannabis was commonplace amongst the ANP including those being mentored by British troops. The hearing was also told that Gulbuddin was a cannabis user. Coroner David Ridley said: "There is a culture that smoking of opium or cannabis is, to them, like to us the smoking of cigarettes."
However, Mr Ridley added that there was no evidence that Gulbuddin was under the influence of drugs at the time of the attack.