In reply to sparkass:
The crack is being monitored (as illustated) and there is possibly a geological survey to be done to try and ascertain what is going on. Signs have been erected to warn about this but not stopping anyone from climbing OB or NCE etc. It is possible to go off right at the end of the gangway pitch on OB and miss out the top pitch !
The area is probably safe - as long as that block stays in place - but no one know when it will go. The sooner it goes the better as far as I am concerned then at least we know where we are - it could be tonight or could be ten years time - at the present time no one knows.
Climb there at your peril !