Used largely as a defective structure the British Army extensively used FOB in Northern Ireland.  In these FOB were Sangin gun emplacement towers with either Bren gun's and GPMG's plus L1A1's fitted with Bren gun Legs were used in an defensive roll. 

   There were tested on many occasions,  but not until the Afghanistan war that these defensive were needed to repel the Taliban who attached them maybe four or five time a day. 

    The Sangin's was often the target of RPG's in Northern Ireland and in Afghanistan.