Mystery Garden Shed Find

I went into the garden shed earlier, to fetch some fat balls for our feathered friends, when I spotted this.
I've taken this photo outside with it hanging on the fence, (C moved it - I didn't want to touch it as I'm really scared of spiders) as it was too dark in the shed, but basically it is a ball shape, about 2 inches (5cm in new money) in diameter with a hole at each side. It is suspended by a sort of cobweb hammock - which may or may not have anything at all to do with it. There is a dead spider on the hanging bit of the "hammock" (you can just see him at the top of the picture).
I personally think that it has been made by a wasp /some wasps. It looks almost woody. We get wasps in the summer on our wooden garden furniture and they seem to be shaving off the top layer of the surface of the wooden furniture, and then they fly off with it. I wonder if this is what they have constructed?
Don't worry conservationists - C has now replaced it back where it was in the shed. 
I'd be grateful for any (half sensible?) ideas.