Do you think it could be rats?
There are no scrabbling sounds of running feet at all. But it's the sound of an animal literally tearing something (wood, plaster?) with its teeth. It's so loud that it sounds like they are in my room but they aren't. It is very very loud. It stops briefly when I tap the ceiling with a stick but then carries on.
For clarification I am sleeping downstairs and the upstairs is an empty (not developed) beamed roof space built in the 1730s.
I have heard the same sound before (it usually starts at 5.30-6.00 and continues for about 45 mins or so) but it's not usually as loud as this!
What the jeff is it?