The Drill Hall was designed in 1882 for the Bloomsbury Rifles by Samuel Knight, a captain in the regiment. It is appropriately military in style, with a tower topped by play-battlements.
All the heads are different, showing the enormous variety of military uniforms of the day. Such a contrast with the drab utilitarianism of the universal beret of today.
Note how the heads become smaller (and therefore cheaper) the further up the building they are.