Brussels summit will be first time head of government has taken floor to outline nation’s conditions for staying in European Union

At around 8 o’clock on Thursday evening David Cameron will take the European Union into uncharted territory. Over dinner at a summit in Brussels, the meeting’s chair, Donald Tusk, will give the prime minister the floor and ask him to outline if, and on what terms, Britain wants to stay in the union, when the vote will take place, and what the procedures should be preceding this historic event dominating Cameron’s second term.

For the prime ministers, chancellors and presidents around the table, it will be a first. No head of government has ever come to a summit with such a message and such a claim. The United Kingdom is staging a plebiscite on whether to stay in. If you do not give me what I need, Cameron will implicitly or explicitly tell the leaders, the EU’s third biggest country may quit.

There are four subjects on the summit agenda. The draft statement, obtained by the Guardian, details what will happen on the first three. Item number 4 is empty except for two letters: UK.

“It will not be a big debate,” said a senior EU official. That is because since his re-election, Cameron has toured Europe to explain his position and gauge support bilaterally with EU heads of government while hosting others at Downing Street and Chequers. “There won’t be anything new,” said several senior people already consulted by the British.

Many in the EU elite are bemused that the question of Europe played no role at all in the UK general election campaign, but became the number one issue on 8 May. Leaders and officials said repeatedly, with some relief, that once Cameron had won his second term they would learn the details of Britain’s aims and hopes. In vain.

Cameron is being advised to remain vague, say informed sources, not to list his demands too specifically lest he make himself a hostage of his own position. There is unlikely to be a detailed written list of reforms that he can be measured against.

“David Cameron’s strategic approach is not to come up with specific things,” said a continental politician who has spoken to the prime minister. “Because then you can fix him and the Tory party will never let him go.”

Senior diplomats in Brussels said the empty space in the summit communique would probably stay vacant because Cameron did not want it filled in.

Officials preparing the summit said Tusk’s aim was to agree on a timeline for negotiations and the procedure. That means they need to know when Cameron plans to hold the referendum so as to adjust their negotiating schedule. But the British take the opposite view – that the timing will depend on the substance and outcome of the negotiations.

One likely outcome on Friday is that the EU leaders charge Tusk with running the negotiations. The British think that likely. The senior EU official said: “There will be a need for political understanding at the top level. This is a job for the leaders, not senior eurocrats. This is the responsibility of the president of the European council [Tusk].”

But the months ahead will be dominated by “technical” and legal discussions between the lawyers, eurocrats and Downing Street aides, he added.

On Wednesday the European commission created a new “taskforce” dedicated to the British question. And it put Britain’s most senior and most experienced eurocrat, Jonathan Faull, in charge of it. A fervent if critical pro-European, Faull, 60, has spent his entire career, 37 years, in Brussels. A lawyer, a liberal, not a Tory, a francophile, he is a consummate Brussels insider.

He knows the legal machinery of the EU’s single market inside out, and has spent recent years dealing with eurozone banking regulation and capital markets. These are critical areas for Cameron and George Osborne – making sure that the imperatives of the 19-country eurozone do not impinge on the single-market interests of the British outside the euro, and that the interests of the City of London, by far the EU’s biggest financial centre, are not disadvantaged by closer eurozone integration.

Senior sources in Brussels say that during the recent round of bilaterals, Phillip Hammond, the foreign secretary, told an EU colleague that the City question was the most important in the negotiations. He demanded a British veto over eurozone and European Central Bank decisions and regulations that affect the City.

Facebook Twitter Pinterest David Cameron will seek to ensure the interests of the City of London are not disadvantaged by closer eurozone integration. Photograph: David Levene

The person he was speaking to guffawed in astonishment. “What? Are you going to give us a veto over Bank of England decisions?” he is said to have replied.

Faull will be central to settling these financial issues. It should not be the trickiest bit of the negotiations.

Without going into detail, the British have pitched their demands under four “pillars” or “buckets” – sovereignty, competitiveness, fairness and welfare. The first is symbolic, focused on the EU treaties’ mission statement of “ever closer union”. It is not entirely meaningless, but hardly worth the fight.

Competitiveness will be agreed relatively easily. They are all singing from the same hymn sheet. Fairness entails the single market structures and financial regulation. There is broad assent that Britain has a case, but these negotiations will be substantive.

Welfare – connected to Cameron’s attempts to curb immigration and free movement of labour in the EU – will be Cameron’s most testing area. He is demanding a four-year benefits holiday for low-paid EU citizens working in the UK and for those unemployed. The government has run up against the limits of what it can do here in British law without breaking EU law and needs changes from Brussels.

Many leaders say no, it is discrimination, and changing the regime would mean opening the Lisbon Treaty, seen almost everywhere outside Britain as a can of worms.

This is not really about content. It's about politics and symbols

The summit will also discuss plans for strengthening the euro over the next decade. The blueprint has been deliberately structured to postpone treaty change until after 2017 specifically because of the British issue, senior sources said.

On welfare there is willingness to tinker with the rules to limit so-called benefits tourism and “social security shopping”, but the changes are unlikely to be as deep as Cameron is requesting.

Europe is crisis-ridden, tetchy and febrile. The last thing most leaders want is the third biggest country to leave. It could be a disaster. A British no to Europe would boost anti-European political movements and help populists make gains all across the union, they fear. And if Britain, traditionally the heartland of euro-scepticism, votes to stay in, it will be a major blow to the populists and a badly needed tonic for Europe, they hope.

“I didn’t ask for a referendum, but we have to deal with it,” said a senior figure in Brussels. “That’s why we have to contribute. It might be complete nonsense but I’m a politician. This is not really about content. It’s about politics and symbols.”