This strange pistol is in the collection of a good friend. He has no idea what it is and nor does anyone else he's met. A real mystery pistol. 

It's brass framed, looks like a semi automatic design, and appears to be chambered in .22LR. The cartridge looks like can be top loaded into a tube magazine running beneath the barrel with empty cases ejecting on the left side where there's a rotating lever plate covering the ejection port. The other strange point is it seems the bottom of the pistol in front of the trigger can pivot open. No one has been able to actually do this but it looks like it could open up somehow.

There are no markings or numbers on the pistol whatsoever.  It seems to be at fault internally as no one has worked out how to cycle the action and the bolt can't be pulled back.

It's likely that this is a home built prototype of some kind but no one really knows. Perhaps someone recognises this design and can shed some light on this strange gun?