The flashpoints remain. If Brown misjudges the reshuffle - read: promotes Ed Balls - then it could spark a revolt among other Cabinet ministers. There's the infamous "signupnow" email still circling around the backbenches, which I imagine has picked up a few more signatures in the wake of Purnell's decision. And then there are the election results. Even though the smart money remains on a disastrous Labour performance, I imagine a few ministers and backbenchers are still holding back until the final tallies are in. How much easier to act publically against Brown, when you can wave a set of dire results under his nose. Who knows? If things fall apart even futher, then even David Miliband might start mumbling about how "I may have said that on Thursday, but after consideration..."
P.S. As Fraser reports, it's sounding increasingly likely that Alan Sugar, the crotchity host of The Apprentice, will be seconded to Her Majesty's Government, most probably as a "Enterprise Tsar". Next Stop: J.K. Rowling as Secretary of State for Children, Families, Schools and Wizardry.
UPDATE: Harman is no longer silent. She's come out in support of Brown. So, too, has Alan Johnson - but his statement doesn't criticise James Purnell.