Last night and again this morning David Cameron asked Nick Clegg to throw him a lifebelt over press regulation and Nick Clegg has decided to watch the PM struggle in the water instead.

Bizarrely and unprecedentedly, there will be two statements on the Leveson inquiry. The PM will speak and answer questions from 3pm to 4.30pm or so and then David Cameron will cede the despatch box to Nick Clegg for a separate statement. Will he stay to listen to the alternative take?

Some (though by no means all) Lib Dems will be thrilled at their leader offering some differentiation, albeit not in the conventional interpretation of “liberalism,” backing state regulation on the press hardly a cause that echoes through their history. Many Tories will be incandescent and muttering about the coalition needing to come to an end.

Don’t expect Nick Clegg’s tone to be too strident in that statement. He still believes in the coalition and the successful working of this coalition is central to his entire political project. There will be some conciliatory language. He’ll want to talk about “differences” not “splits”. But if you go for a separate statement in an unprecedented way and open up the possibility of voting in a different direction then you are inevitably inviting headlines like the one at the top of this blog.

I still suspect David Cameron will be looking for a breathing space to let the press come up with something tougher than the self-regulation it’s already produced. That, Nick Clegg has decided, isn’t enough and he must now decide if he will push that to a vote in the Commons, splitting off from the Tories to vote against David Cameron’s preferred option.

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Even without a vote, this is Nick Clegg’s biggest act of defiance since the decision to dump the prime minister’s cherished boundary review. Opposition to boundary changes was probably more potent because it was in the coalition agreement (and central to the Tories’ electoral plans). But the boundary review didn’t come to a vote in the Commons – not yet anyway. Press regulations easily could come to a vote. The PM could then face a defeat at the hands of the combined forces of Labour, the Lib Dems and many Tories. His advisers have said he’s braced for this and would simply ride on with his policy safe in the knowledge that only the government can be sure of getting a bill through parliament and he can’t be ambushed with a bill he doesn’t want.

This all raises another question about why the PM is announcing his direction of travel so soon after receiving the Leveson report? It’s usual to “take note,” ponder for a while and come up with an approach after a few weeks. One seasoned politics academic said he was staggered by why we were having “government by speed-reading like something out of Harry Potter.”

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