That was the BBC News headline and:
The men, who were serving as part of an advisory team, were killed on Saturday as they provided security for a meeting with local officials near Patrol Base Attal....near a base in the Lashkar Gah district of Helmand province....
The London-based Defence Correspondent adds:
The rise in "green-on-blue" killings, now averaging one a week this year, is having an impact on trust in a relationship which is key for Nato's exit strategy. Nato says the attack on Saturday is the 16th incident this year in which Afghan soldiers or police - or insurgents wearing military uniforms - have turned their weapons on foreign troops, bringing the death toll from such attacks to 22 so far this year. That toll is higher than at the same time last year...
Link:http://www.bbc.co.uk/news/uk-18047242

Personally I think the impact is growing at home as it challenges the official narrative of a handover to Afghans akin to "people who kill us and you want us to stay longer?"