To this day Field Officers, those of the rank of Major and above and the Adjutant of a Battalion, wear spurs in boxed boots when in ceremonial or mess dress uniform. This dates back to an era when such officers would have been mounted on horseback where more junior officers commanded and fought on foot. Field Officers do not wear spurs when on parade due to the difficulty marching when worn.
All officers wear slung sword belts. This allows the sword to hang in the correct location to be drawn when mounted. The sword is placed with the guard forward when hanging and the belt straps are adjusted so it hangs as seen in the image.
Originally all officers, regardless of regiment or arm of service, wore their swords slung for use when mounted. Then General Sir Sam Browne VC lost an arm in a frontier skirmish in India in 1858 and invented the Sam Browne belt to accommodate his disability. His style of belt became popular in India and was used across the Army after his retirement. Gurkha officers then wore black Sam Browne belts with silver fittings (except in No.1 and No.3 dress when pouchbelts were worn). In 1975 starched shorts and shirts ceased to be used (in which order of dress a Sam Browne was required) and it was decided pouch belts would be worn in all orders of dress. Henceforth only slung swords were worn.