A portable industrial search or spot lamp, probably dating from the 1930s onwards, and possibly ex military in origin. I have only ever seen this exact design once before (see last pic, Ancient Lights film prop hire company has two), and it's a stunning design and very solidly built. 40cm tall overall, and the light is approx. 20cm diameter, so a fairly big unit.
I haven't tested it, but as it is just a wire to a bulb holder I can't imagine it doesn't work, and if it did would be very easy to fix. This is a really stunning piece and would look great as a feature piece in an industrial ...