Seems to have just gone down, 9am UK time (4am Eastern, 1am Pacific)

EDIT - actually, looking at the graph on a monitor rather than my phone, it looks like it went down a couple of hours before that.

EDIT 2 - seems to be back! 10:52 UK time. It's running quite slow though.

EDIT 3 - gone again? 14:20 UK (EDIT 3a - Back almost immediately 14:25)