Jean-Claude Juncker, the centre-right candidate for European Commission president, said on Wednesday (23 April) that renegotiating the UK’s European Union membership would be one of his priorities if he wins the job.

At a press event in Brussels on Wednesday, Juncker put forward his five priorities in case he becomes the next Commission president after the May European Parliament elections.

In a move to charm the UK's prime minister, David Cameron, the former Luxembourg prime minister stressed that “as commission president, I will work for a fair deal for Britain”.

“No reasonable politician could neglect we have to find solutions for the political concerns in the UK," Juncker said, stressing: "We have to do this to keep UK in.”

Referring to an opinion piece the UK premier wrote in the Daily Telegraph, the centre-right candidate of the European People's Party (EPP) said: “I will be ready to talk to him about these demands in a fair and reasonable manner.”

Juncker added that other EU member states will have to accept some of the UK’s demands in order to placate London, which have seen the UK obstruct EU decision-making during the euro zone sovereign debt crisis or on the free movement of people.

“Countries have to accept that the UK will never participate in the euro [currency]. Nor will it become member of Schengen [passport-free area]. And it will stay outside of certain EU institutions, such as the European Public Prosecutor's Office,” he said.

In exchange, he added, “they have to listen to our requests when it comes to stronger powers for the monetary union.”

But the EU has red lines, too, Juncker ​told EurActiv: “A good functioning of the internal market should not be harmed [and] every member of the European Union will have to respect the basics freedoms, including the freedom of movement.”

Ahead of national elections in 2015, Cameron promised to give Britons an in/out EU membership referendum if he is re-elected. A recent poll showed 35% British voters would vote to remain in the EU, 32% would leave while 27% are undecided.

The outlook of an ‘out’-vote in the referendum could force the EU to make considerable concessions when re-negotiating with London. But “a referendum perspective should not be used as blackmail,” Juncker told EurActiv.

Experts have argued that such a reform of the EU institutions would require a treaty change. But EU leaders are hesitant to open up this Pandora's Box, fearing ratification problems in one of the 28 EU member states. Juncker, for his part, said he was confident that special arrangements for Britain "would not require treaty change.”

The lead EPP candidate for the European elections visited Brussels in a pit stop on his campaign trail across EU member states. The Luxembourger needs to get elected as Commission president in a vote in the EU Parliament, after the elections. But, crucially, he first needs to be nominated by EU heads of states in the European Council.

In February, German chancellor Angela Merkel endorsed Juncker as the lead candidate for the EPP, which includes her German party, the CDU, as a member.

David Cameron and the UK government haven’t endorsed any candidate so far. Their Conservative party is heavily opposed to the idea of pan-European candidates for the EU executive’s lead position.

But Juncker is the first common candidate to put the UK’s renegotiation demand on this campaign’s political agenda, which could bring him an advantage in getting a British endorsement at a later stage.

‘No enlargement in next five years’

Juncker is the frontrunner of five so-called ‘Spitzenkandidaten’, nominated by pan-European parties, to take on the role of Commission president [Read our LinksDossier].

His other priorities, outlined at yesterday’s event, included jobs and growth, a reform of Europe’s energy policy, finalising the free trade agreement with the United States (TTIP) and bringing the social dimension into the Economic and Monetary Union (EMU).

“The eurozone should be managed by the Commission and by the Eurogroup,” said Juncker, adding that the latter “should be chaired by a full-time president”.

Many have called for deep restructuring at the European Commission for the coming term (2014-2019). Amongst the proposed reforms is the nomination of a ‘budget tsar’, a Commissioner with extended powers who would oversee portfolios related to economic and financial policy and potentially chair the Eurogroup of eurozone finance ministers.

“A Commission has to be structured in a different way as far as its internal structure is concerned,” said Juncker. Still, he added, “we have a decision by the European Council that each and every member state should be represented by one commissioner,” which rules out suggestions to downsize the EU executive.

On the issue of enlargement, the Luxembourger took a sharp tone, saying “I’m of the opinion, like so many of my colleagues in the Council, in the Commission, in the Parliament, that there will be no new accessions in the next five years.”

Formal negotiations with Serbia kicked off in January while countries like Turkey, Macedonia or Montenegro have been formal candidate countries for a longer period.

But at December’s European Council, hopes for swift accession agreements were dashed: several EU countries expressed their opposition to accept new members in the club.