Many Middle Eastern and Indian cultures associated wisdom and power with facial hair. As a result, facial hair and moustaches became increasingly common among British soldiers during the great wars. During the Crimean War, all ranks were encouraged to grow full beards during winter. More recently, the British Army has been seen sporting a full range of stubble, moustaches and beards on Ops to blend in.

Given the current Terrorism Level, it also helps to 'blend in' in a civilian environment.