Officers should be 'armed' only with a stout walking cane to thrash Johnny Foreigner with when he gets uppity, or else have his batman carry his Purdey in the event of a 'general uprising of the native populace'.
I understand that it is permitted to point in the general direction of the enemey with either a swagger stick or fountain pen.
All officers up to and including the rank of Lieutenant Colonel are issued the SA80 rifle (or carbine if in a specific role demanding it) as their personal weapon. In common with all other soldiers they may also be issued and carry a pistol as well as, or instead of, their rifle where appropriate.
Officers above the rank of Lieutenant Colonel can elect to have either a pistol or a rifle as their personal weapon.
Officers are trained to use other weapons, particularly within the infantry, but would usually have no reason to carry them as a personal weapon.