Sorry to sound like a tired old record, but one of the reasons the phone-hacking story will not go away is because at so many stages, the key players have handled it so badly.

The latest example is the sudden overnight discovery of emails implicating Andy Coulson in the payment of cash to police officers while editor of the News of the World. How come all the previous internal and external investigations failed to find them? How come they emerge now, just as the Commons is about to debate the issue, and News International would probably prefer MPs to be talking about Cameron, Coulson and the past than the latest revolting allegations?

If I were Coulson, I would be feeling not just nervous, but hung out to dry. If I were Cameron, I would realise the point has come where he has to put all personal relationships to one side, and speak to and for the genuine public interest here.

That means an inquiry not merely into phone-hacking and the police mishandling of it – the subject of today’s debate – but an inquiry into the practices of the press, and the extent of criminal activity, including the network of journalists, private investigators and police.

This was exposed by the Information Commissioner some time ago, in a report which surprise surprise got zero coverage, and which showed The Daily Mail to be the worst offender.

Any inquiry must look into all newspapers, and it would be in the interests of all newspapers to support it. The tipping point has been reached where the public now see the press serves our country and our culture badly. It is up to David Cameron to point things in a different and better direction.

That means an inquiry where the big figures of the media, from Murdoch, Dacre et al down, and the police, and people who have been failed by both, can be central to a debate which leads to a new a different culture and a new and different regulatory system which is not the joke that is the PCC.