John Bowkett (attrib) prototype air pistol

John Bowkett (attrib) prototype air pistol 

With thanks to Anne. She says:

This is a pistol I picked up at an auction at least 15 years ago and which was catalogued as a 'John Bowkett prototype'. It has absolutely nothing on it anywhere, no name, no serial numbers, nothing. Remarkably it's still holding the same air as when I bought it, so it still cocks and fires despite living in a drawer! It has a very bizarre loading system for the pellet; you have to unscrew a cap at the end of the barrel, pull the barrel tube out and then pop a pellet in the end before reassembling it. Cocking is at least straightforward with just a lever to pull.