Not a huge surprise; he's made a large number of gaffes.
He has done but the media seem (from what little I've read; only just got back from Caernarfon like a few minutes ago) to be taken the thing about 'personal reasons' more seriously than they usually do. Yeah, well, if that's the case I hope it's not health related as well.
Anyways, this has sparked a mini-reshuffle at the top, as this sort of thing is wont to do. Ed Balls as Shadow Chancellor of the Exchequer, Yvette Cooper as Shadow Home Secretary, Douglas Alexander as Shadow Foreign Secretary. Other changes as well, obvs.