This is the Sergeant's sash, a distinction of his rank. Only Officers and Sergeants were allowed to wear sashes. A sash was supposed to provide a stretcher to remove a wounded Officer or NCO from the field. Note that the Sergeant's sash has a blue stripe. This matches the colour of the cuffs and collar of his coat. Officer's sashes would be made of silk, whereas Sergeants' sashes were made of wool. Note that the sash is knotted on the right, a further indication that this Sergeant belongs to the light company. All other companies knotted their sashes on the left.