Good day to bury bad news? Dig a mass grave

How much more bad news is Westminster thinking of burying this afternoon? An announcement from the Palace that William and Kate have had second thoughts, perhaps? Let's face it, you could announce almost anything now and there'd be no room on the front pages to carry it.

Of today's breaking stories, the resignation of Andy Coulson is the big one. It had been coming for a long time. While Coulson still maintains his innocence in the News of the World phone hacking saga, the pressure has got to him and today was the perfect day to admit it.

"I stand by what I've said about those events," he said, "but when the spokesman needs a spokesman, it's time to move on." (A nice variant on Alastair Campbell's axiom, "Once you become the story, it's time to quit.")

For Coulson's boss David Cameron, it is a huge blow. The PM's extraordinary ability to ride above the fray is mainly due to his roots and upbringing - Old Etonian arrogance, if you like - but Coulson's cool head has played its part too.

Spin doctors are not two-a-penny - the Mole has dabbled in the dark arts himself in a previous life - but Cameron will surely find himself another one, who comes with less baggage.

Tony Blair's admission to the Chilcot Inquiry, also breaking this morning,  made a good headline - 'Blair admits he ignored Goldsmith's advice'- but as my colleague Crispin Black writes for The First Post today, whatever comes out by the time his grilling is over, Blair "will rejoin a security detail that would be over the top even in a banana republic, and be Range-Rovered off into the sunset to spend more time on his perma-tan and his millions."

As much as Crispin Black might wish the opposite, the Chilcot Inquiry has no power to apportion blame for the Iraq invasion, let alone chop Blair's head off.

Which brings us back to the start of this momentous day in Westminster, and the overnight news that Alan Johnson quit the shadow Cabinet because his wife allegedly had an affair with his personal protection officer and that Johnson is to be replaced as shadow chancellor by Ed Balls.

Coulson's going will soon be forgotten. But the Mole sticks by his line in today's earlier posting - that Ed Balls's appointment will prove pivotal to Ed Miliband's fortunes. It will make him or break him. ·