What did we learn today from David Cameron’s formal opening of the renegotiation effort? He’s going into these talks saying he wants all four of his four negotiating demands. Well, sort of.

The toughest of the four, reducing benefit entitlements for EU workers while they’re in the UK, did sound like it might just be approached a bit laterally.

David Cameron said: “Now, I understand how difficult some of these welfare issues are for other member states. And I am open to different ways of dealing with this issue. But we do need to secure arrangements that deliver on the objective set out in the Conservative party manifesto to control migration from the EU.”

I asked what these “different ways” would extend to and whether he would rule out simply raising qualification for some benefits for UK citizens in order to (rather stealthily) raise the qualification for EU citizens. He didn’t really engage with the question.

Overnight, Downing Street raised the stakes on the benefits issue by putting out statistics which, it said, showed nearly half of new arrivals from the EU are claiming benefits and about 66 per cent of them (or 148,000 EU migrants) are claiming tax credits.

It’s not clear yet how these numbers were compiled and they appear to be much bigger than past estimates. No full tables or explanation is yet available.

I asked what it would say about David Cameron’s self-proclaimed “substantial” renegotiation, which he claimed today would create “a new kind of European Union”, if the whole negotiation was wrapped up and the vote done and dusted a year and a half before his original deadline.

He insisted that all speculation about timetables was just that and though he was in a hurry to get going on this, he would be patient in negotiations.

Nigel Farage told me that he acknowledged that an early referendum was against his side’s interests. He admitted the “out” camp was divided, some big egos were at play and he was trying to make peace between the two. He said momentum was with the “out” camp and that was why he thought No. 10 would prefer and was going for an early referendum.

We heard again today from David Cameron the argument that voting to stay in Europe is all about national security. One old Europe hand said: “They’re hoping Putin will win this for them.” George Osborne deployed the argument heavily in Berlin last week.

And it sounds like the government has decided to layer another message on as well.

The government’s been weighing up for some time whether to shove the draft British bill of rights reforms the other side of the December EU summit or not. Could it exacerbate David Cameron’s difficulties with his own party as hardline Eurosceptics complain of two reforms that don’t measure up to their hopes – an EU negotiation that’s too light and a justice reform that doesn’t promise withdrawal from the European Court of Human Rights?

Today David Cameron sounded like he’s made the choice to bring forward the justice proposals before the December EU summit in the hope that they can help with the mood music that much is changing – he’s certainly decided to talk them up at a critical moment.

His opponents will say this is all a sign that not much is actually changing at all, it’s all chaff to distract from a relatively thin and highly achievable list of negotiation demands. Allies of the PM say it’s not like that and his team has its work cut out getting progress in Brussels.

The one-on-one “confessional” discussions between Donald Tusk’s European Council team and the other 27 member states’ ambassadors to the EU start next week.

The letter published today to Mr Tusk is supposed to provide an agreed hymn sheet that individual officials can work off in these discussions.

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