This British Pattern 1876 socket bayonet has the scarce Mk1 scabbard. The blade ricasso has the number 3987 together with the ordnance marking of the broad arrow over WD.
The scabbard is the Mk1 model which varies from the more common Mk2 model having three rivets to the internal spring and a small rivet to the chape. There is a number “71” stamped to the frog stud and “26” to the locket rim. (Reference BCB B187 and page 148).