St Jame’s Palace is one of the Royal Palaces in London and dates back to the Tudors. Whilst no longer the monarch’s primary residence it contains the official residence of many other royals and has many of the administrative offices for both officials, miitary personnel and royals. As such during the interwar period there was a ceremonial guard and today’s postcard shows the changing of this guard, sometime in the 1920s:

The guardsmen can be seen marching behind their standard bearer. It is the winter months as they are dressed in the atholl grey greatcoats issued to the guards:

They are all wearing the white leather Slade Wallace webbing sets. These had been obsolete since the Boer War, but remained on issue for ceremonial duties right through until after the Second World War.
With their backs to the camera, the buglers of the guard can be seen:

The guardsmen’s bugles can be seen hanging down behind their buttocks. Interestingly the equipment worn seems to vary, with some just wearing belt order whilst others have full equipment with cross straps and rolled blankets worn at the waist. To the left can be seen an officer, distinguishable as he wears a double breasted greatcoat in contrast to the guardsmens’ sngle breasted versions. In his hand he carries a drawn sword, a universal symbol of an officer.