Solved! Go to Solution.
It's hard to tell. It could be that some component in the Home Hub is fried.
Or perhaps it's the microfilter or filtered faceplate on the master socket (as applicable). If you have a spare microfilter, it could be worth trying the test socket of the master socket. http://bt.custhelp.com/app/answers/detail/a_id/13567/~/testing-for-faults-with-a-line-box-or-bt-infi...
Or it could be something got zapped at the cabinet and the problem isn't in your home at all.
We managed to get another hub and it worked! I wasn't too hopeful as the old hub appeared to turn on and work (except for the lack of connection). There must have been something fried inside it as the new hub works perfectly!