Cameron's EU reform drive sidelined at tense summit

British Prime Minister David Cameron will arrive at an EU summit in Brussels on Thursday to find his referendum reform push sidelined by twin crises over Greece and migration.

Rather than a lengthy conversation about the reforms Britain wants, sources expect European leaders to discuss the issue only briefly on Thursday night before agreeing to move to the next stage in the process -- technical talks.

Cameron's plans to recast Britain's relationship with the European Union before a referendum on leaving the bloc by the end of 2017 have hogged headlines at home since he won last month's general election.

But for other European countries battling to keep Greece in the eurozone and grappling with an influx of migrants from Middle East and African trouble spots, substantive talks on the issue as a group will have to wait.

Britain has stayed out of the eurozone and is opting out of a very controversial programme to relocate migrants around the EU.

Cameron said that Thursday and Friday's summit, the first time the bloc will discuss the reform push collectively, would "kick off a process to work through the substance and to find solutions."

A senior EU diplomat speaking on condition of anonymity added: "I don't detect at the moment, given where we are, that there is an enormous appetite to have a big, comprehensive discussion of the British question."

That is "undoubtedly coming in the second half of the year," the source added.

Many European countries remain wary of Cameron's plans. French economy minister Emmanuel Macron warned against creating an "EU a la carte" in a BBC interview Wednesday, expressing a concern shared by many.

Meanwhile, Queen Elizabeth II used a state visit to Germany, during which Cameron also held talks with Chancellor Angela Merkel, to warn that "division in Europe is dangerous" Wednesday.

- Months of work ahead -

As discussions take place behind closed doors, Cameron -- who wants to stay in the EU if he gets the right changes -- faces increasing pressure in his centre-right Conservative party to be more specific about what he is pushing for.

Highlighting wider concerns, three senior eurosceptic lawmakers published a pamphlet last week explaining why they would campaign to leave unless Cameron secures "fundamental change" to restore Westminster's primacy over Brussels.

Officials point to four broad areas of negotiation -- improving competitiveness; ensuring fairness for non-eurozone countries; protecting sovereignty, including opting out of the EU's commitment to "ever closer union" and limiting access to benefits for migrants.

Cameron's Europe Minister, David Lidington, has already warned against revealing specific details of the talks for fear of prejudicing the negotiations.

"My advice to my boss would be on no account publish a full negotiating position because I don't think that's sensible in any sort of negotiation at all," he told reporters last month.

Instead, the public announcements will likely be kept generalised as the next stage of the reform process -- involving detailed technocratic and legal discussions which could take months -- unfolds.

Senior EU civil servant Jonathan Faull, a Briton, has been appointed to lead a taskforce on the British referendum in Brussels.

While the referendum must take place by the end of 2017, ministers are keen to hold it sooner if possible and some senior Conservatives now believe it will take place in the second half of next year.

Whenever it is, Cameron faces a delicate and difficult balancing act to keep both the negotiations and his own party, which has a long history of euroscepticism, on track right through to the referendum.