Coulson was editor at a time when his paper was caught up in a phone-bugging scandal which resulted in a couple of low-level operatives doing time. That wound has burst open again and the Prime Minister's office is having to go on and on about what a sweet person Andy Coulson is and how he didn't know a thing. We've seen this defence before- and it prompts questions about the competency of the person who hides behind it.
So is Coulson a sleazy crook who allowed underlings to carry the can for him, or a dewy-eyed innocent who didn't know what his staff were up to? Whichever way the judgement goes there's going to be a hell of a lot of spinning to be done.