This is a really attractive dagger that I cannot resist comparing in appearance to plug bayonets, however the hilt would suggest that use obviously not likely, especially with the knob type pommel. Since plug bayonets often were used aside from the intended use as daggers or hunting knives, it seems that they did in some cases may have remained as an accoutrement even after obsolete.Possibly ceremonial or dress example of one refurbished?
I may be way off base on this as I saw nothing similar in Evans ("The Plug Bayonet") but thought I would present the suggestion anyway
Fire at will !