Disturbing footage of Apache attack helicopters killing people in Afghanistan is being shown to frontline British soldiers in "Kill TV nights" designed to boost morale, a television documentary will reveal.

The discovery of the practice comes in the wake of the damning verdict of the Baha Mousa inquiry into the conduct of some in the military. It casts fresh questions over the conduct of soldiers deployed abroad and has provoked a furious response from peace campaigners.

Andrew Burgin from Stop the War last night described it as the "ultimate degradation of British troops", comparing it to the desensitisation to death of US soldiers in the final stages of the Vietnam War.