From the BBC article:
I never served in the military, but is an accidental explosion of explosives/munitions carried by a team member considered "friendly fire"? Maybe it's my lack of knowledge, but the BBC's headline seems more like shit-stirring than accurate reporting.
I have read several articles on this and they are all very sketchy on details. The only thing written in all of them is that there was some kind of accidental explosion within the Special Forces group which killed 2 and wounded 5. Tonroe was one of the 2 killed.
But you are absolutely right. If one of the soldiers had a pin pulled on a grenade or if some other munitions exploded accidentally, then this is far from friendly fire. They are using the term 'friendly fire' either out of ignorance or by malice. I don't know.
It was some kind of accident by all reports, not friendly fire. Don't know why they are making such a fuss over the one British SGT since one American was killed with him and five others were wounded and evacuated for treatment. From reading these articles it would be easy for the casual reader to get the impression that the SGT was the only casualty, and he was somehow killed/murdered by Americans. This is ridiculous of course, but as we all know truth doesn't really matter to most 'news' operations today.