I do not have photographic evidence, but I can confirm it is a badger that is getting into the compost bin.
Fortunately for the culprit, I braved the strong winds to collect up the mess he (or she) had made. I am not sure who was most surprised when I lifted the lid of the compost bin.
The badger was not as big as I expected, and it sort of sat there for a while. I sort of stood there very surprised. Obviously it could not find a way out, the same way as it got in. Compost must have fallen from above the "tunnel" it dug out. I had a large dust pan with me, and assisted the badger to climb out.
It could get its front legs on the top edge of the bin, but was not strong enough to climb out.
Tis a good thing I went out there this afternoon, to tidy up, or he would have run out of oxygen.