The European summit this week has been expected by Westminster journalists to be a "four-shirter" for some time now. This refers to the number of changes of clothes that the travelling press need to pack.
The Foreign Office has dreaded it for even longer. I recall a conversation with a top civil servant more than six months ago in which the "seven-year renegotiation of EU financing" was mentioned, and the need to get whatever is agreed through Parliament. I wasn't sure what was meant, but it sounded ominous, and now I realise why.
The Government was defeated in the Commons at the end of last month, when Labour voted with Conservative Eurosceptics on an amendment calling for a cut in the EU budget. David Cameron has no chance of achieving such an outcome in Brussels. As Downing Street pointed out, fruitlessly, more countries benefit from the EU budget than contribute to it, and any deal has to be agreed unanimously. If agreement is not reached, the existing spending limit would roll over, adjusted for inflation. Because the limit is currently higher than actual spending, this means that, if any country vetoes a deal this week, spending could go up in real terms.
The best that Cameron can hope from a deal would be a real-terms freeze in spending. Our ComRes poll today shows how unpopular that would be: 66 per cent of voters say the budget should be "cut rather than frozen".
That would be only the start of his trouble. He now seems doomed to repeat the history of leaders of both main parties who have come to grief on Europe, because two big things have changed. One is that the Labour Party has rediscovered the joy of disciplined opportunism. As John Smith did over the passage of the Maastricht Treaty through the Commons in 1992-93, Ed Miliband has decided that, because everyone knows that he supports Britain's membership of the EU, he is allowed to lead his party to vote in ways that put that membership at risk.
Pro-European Labour MPs, although they were unhappy, voted as instructed with the Tory Eurosceptics. Lord Mandelson, the pro-European former MP, writing in the Financial Times last week, observed with meaningful understatement: "This generation of Labour leaders is not anti-Europe but it is not anchored as firmly in the pro-EU attitudes of the past."
Cameron's bigger problem is a more significant change that happened last month. Lord Mandelson touched on it in his article, when he revealed that the Prime Minister had once said to him: "If you put two Conservatives in the same room it will not take them long to fall out over Europe."
Well, two Tories who have been put in the Cabinet room are Cameron and Michael Gove, the Education Secretary, and now they have fallen out over Europe. After the Tory party conference, Gove was reported on the front page of the The Mail on Sunday as saying that the UK should renegotiate its membership of the EU, and leave if it does not get what it wants. Such a dramatic story is normally followed by a statement from the minister, explaining how his views are consistent with the Prime Minister's. Because Cameron says that Britain's future is in Europe.
But there was no "clarification". The words attributed to Gove by "friends" were not denied, probably because they came from a dinner Gove attended with Mail on Sunday executives. Almost invisibly, collective ministerial responsibility is breaking down. Not only is the Government divided between the two parties in the coalition, the Tory part is divided between those who want to stay in Europe and those who have "told friends" that "we are a major trading nation and that gives us considerable bargaining power with the EU whether we leave – or stay in". This is odd, because Gove is so close, personally and politically, to the Prime Minister. And yet neither side pretends in private that their views are anything but fundamentally different.
Gove's position seems popular. Our ComRes poll finds that 58 per cent of voters agree that "If some EU powers cannot be restored to the UK, we should leave the EU", and only 18 per cent disagree (the rest don't know). I suppose that if you were Cameron and tempted to clutch at straws, you might look at the opinion polls as Harold Wilson did in 1974-75, and hope to claim to have restored some powers to the UK. James Callaghan's "renegotiation" to ease imports of New Zealand butter was enough to win the referendum to stay in.
But that would be hazardous for the Prime Minister. The rest of Europe has more important things to worry about than trying to help him solve his domestic problems, which are going to get worse. Ukip came third in the Corby by-election last week and is running almost level with the Liberal Democrats in the opinion polls. Many Tory MPs are frantic about the appeal to their voters of Nigel Farage's anti-EU protest party.
With Gove, such a close ally in the Cabinet, saying that Britain has "nothing to fear" from leaving the EU, it is hard to see how this is going to end well for Cameron or for the Conservative Party.