Not particularly my field, but it looks from the pics that the pommel, quillons and badge/plaque are brass, which would likely point to naval use. If "normal" military use I would have thought iron/steel for these. I'm not good at decyphering this type of script, but is it RN? (Maybe Royal Navy??) 
Nice interesting piece. 
Regards Stu
		 
		
		
		
		
		
		
		
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