European Union leaders gathering tonight in Brussels for their last summit of the year are unlikely to relish their dinner.
For instead of enjoying a rare moment of relaxation, they will spend their evening hearing British Prime Minister David Cameron outlining the conditions under which Britain is willing to remain part of the union.
Mr Cameron is unlikely to score a diplomatic triumph. Essentially, his problem is that while all member states want Britain to stay, few are prepared to make the concessions the British are demanding.
Mr Cameron has formally set out four demands. One is that Britain be exempt from the application of a promise in the EU founding treaties which pledges all members to work towards "an ever-closer union". Another calls on the EU to dedicate itself to eliminating inefficiencies and promoting free trade. Both are of symbolic rather than practical value, so it should not be hard for Britain to bag these concessions.
A third demand is more substantial: Mr Cameron wants a guarantee that despite Britain's determination to remain outside the euro single currency zone, the City of London, Europe's top financial centre, should not be discriminated against in future European laws.
France and several other countries resent this demand and worry that London will gain an unfair financial advantage. Nevertheless, the chances are good that Britain will get its way on this issue as well.
The main problem for Mr Cameron is his demand that Britain be allowed to refuse welfare payments to other EU citizens who come to the United Kingdom.
At present, such EU citizens are entitled to payments from the first day of their arrival. Although no accurate figures exist, abuse of the system is widespread, with some people from Eastern Europe travelling to the UK with the clear intent of drawing welfare benefits.
Mr Cameron wants to ban East Europeans from entitlement to any welfare for four years after they settle in the UK. But that is strenuously opposed by other EU members as it violates fundamental principles of the union: the free movement of people and the obligation not to discriminate between EU citizens.
Mr Cameron is expected to say he is prepared to compromise on this point. "We have made very clear that if people have other ideas, we are absolutely prepared to listen to them," said British Foreign Secretary Phillip Hammond.
But there is little room for compromise, partly because other EU leaders resent Britain's constant demands for special treatment, but also because any deal reached between Europe's politicians could be picked apart by European courts.
Earlier this year, when his ruling Conservatives faced what then seemed like a mortal electoral threat from the nationalist UK Independence Party which pledged to pull Britain out of the EU immediately, Mr Cameron promised that, should he be re-elected, he will renegotiate Britain's EU membership and leave it to voters to decide whether to stay part of Europe. He was re-elected, and now has to honour the pledge.
Mr Cameron wants to conclude negotiations with the EU within weeks, paving the way for a referendum by June. And there is not much doubt how he plans to do this: "What I want for my country is to reform the EU, to make it better, and then recommend that we stay in the EU because we need those trade links, we need those markets open, we want that influence in the world," he told voters recently.
Yet getting what he wants is easier said than done, for Mr Cameron has to figure out how to squeeze concessions which appear serious enough to the British electorate, but are not too serious so as to annoy other European electorates. In time-honoured fashion, EU leaders are likely to avoid a decision tonight, kicking this thorny problem to their next summit in February.
But time is not on their side: the latest British opinion polls show voters' desire to leave the EU is gathering pace: if the referendum was held today, 42 per cent would vote to stay, and 41 per cent to leave.
And that could give all those at dinner tonight mighty indigestion.