Just chiming in with everyone else that this is a spadrron-type, European/probably UK. I post this one only to show the folding back guard (yours appears to be missing) on the m1786 pattern. I think the issue with these types is similar to NCO swords. There appears to be room for variation depending on branch, rank, specialty, etc.
http://myarmoury.com/talk/viewtopic.12970.html