This is a really interesting piece of WW2 Trench Art style. The  2pdr cartridge has been cut down to a height of approx 2 inches. A 1901 farthing has been bent and fixed to the lip of the case to act as a cigarette rest. on the side of the case is an Australian Imperial Force badge. There is an inscription on the bottom of the case which is HMFS La Capricieuse. In addition, the case is dated 1939 2 Pdr.

I have carried out some research and there was a ship named HMS La Capricieuse

La Capricieuse was a ship of the French Elan-class minesweeping sloops. She was built by Chantiers Dubigeon at Nantes and launched on 19 April 1939. After the Fall of France she was at Portsmouth and on 3 July 1940 she was seized by the Royal Navy.

So this piece has some real history