What is it?
 

I know this is not old. The blade appears to be some type of tool steel, maybe for woodworking. I handle is carved horn. I think of Ganesha. Is is Indonesian? I could not find anything on the manufacturer's name J. SELWOOD which I assume is British given the two crowns. Any ideas about the origin?

From what I can see in your pictures it does look like an old British made wood lathe turning chisel made into a dagger.

I think Tim's bang on the money, its a reworked wood chisel. It was common for craftsmen to have their moniker stamped or engraved on their tools. Afterall without them they could not work and quality tools are revered.
It is a possibillity that the name is the previous owner of the chisel and not necessarily the manufacturer.

I would add that there is more than a distinct possibility that the hilt represents a Makara .

Definitely an Indo shiv . ;)

You hit the proverbial nail on the head there Rick. I had been searching for images of Ganesha to compare to and found none with all the tusks. Once I searched for Makara I found numerous similar images. See the attached photos. Curious that this elaborate hilt is connected to such a utilitarian blade that is blunt except for the tip which is needle sharp. As you said, it's a shiv.

Thanks

THE POMMEL IS INDEED VERY ELEPHANT LIKE BUT THE SCALES ON THE GRIP WHICH WOULD BE THE BODY OF THE BEAST ELIMINATE GANESH. I DON'T KNOW MUCH ABOUT A MAKERA BUT IT IS INTERESTING THAT THE HEAD SOMETIMES LOOKS ELEPHANT LIKE AND AT OTHERS LOOKS LION LIKE. PERHAPS THE SEA SERPENT WITH THE LION HEAD THAT REPRESENTS SINGAPORE IS A MAKARA :confused: NICE LOOKING DAGGER MUCH COOLER THAN A WOOD CHISEL