Truth be told, not too many horror movies spook me out at all when I originally watched them, but this one did.
That claw under the floorboards in particular.....
A host of familiar faces in it too, including - inexplicably - Zoe Herriott, Betty (Frank Spencer's wife), Carrot off Catweazle and The Master off Doctor Who, who is posing as a priest once again, a la THE DAEMONS.
I won't bother trying to fit all these things into their varying continuities!!
But yeah, something about this film that is - or was - unusually creepy.