Biggest moth ever

Now this is a big moth. For size comparison, see the dead normal sized moth on the ground. This moth was the size of a small bird, I kids you not. A moth like this would not be eating your clothes, it would be out wearing them. It is not dead just apparently resting. I am loathe to move it on, as you would be.

Update

I got back from the shops, and it was gone.

Update 2

I checked the Internets it was probably a Giant Wood Moth. It is a shame I didn't see it fly away, apparently its wingspan is 10"