Angela Merkel warns David Cameron not to make 'threats' over Jean-Claude Juncker's bid for EC presidency

The German Chancellor said EU politicians should not resort to “threats” as they decided who should become the next President of the European Commission. It followed reports that Mr Cameron had warned Ms Merkel the appointment of Mr Juncker, who believes in greater European integration, could boost the prospects of Britain voting to leave the EU in the 2017 referendum he has promised.

Speaking alongside Mr Cameron after a summit of four centre-right leaders in Sweden, Ms Merkel voiced her irritation at his public campaign against the former Luxembourg Prime Minister’s bid for the Brussels post. Ms Merkel, the most powerful national leader in the 28-nation bloc, told a press conference: “I am for Jean-Claude Juncker. But when I made that statement in Germany I also made the point that we act in a European spirit, otherwise you would never reach a compromise. Thus we cannot just consign to the backburner the question of the European spirit. Threats are not part and parcel of that spirit. That is not part of the way in which we usually proceed.”

Mr Cameron will face questions about his attempt to thwart Mr Juncker when he makes a Commons statement on Wednesday, and later when he addresses Tory MPs, many of whom want to stop the appointment of a man they view as an arch-federalist.

British officials hope Ms Merkel’s remarks were for domestic consumption in Germany. She is under pressure to back Mr Juncker because he has the support of the European People’s Party, the mainstream centre-right party in the EU. Aides said Mr Cameron would lobby other EU leaders before they meet in Brussels on 26 June.

Jean-Claude Juncker believes in greater European integration (Getty)Today Mr Cameron came close to confirming he had made clear in Brussels last week that Mr Juncker’s appointment could boost the anti-EU campaign in Britain. He said: “The decision about whether to stay in Europe will be for the British people in a referendum by the end of 2017. Obviously the approach the EU takes between now and then will be very important. If we can achieve reforms, if we can demonstrate openness, competitiveness, flexibility, less interference, reform – if people are capable of taking the EU forward, that will be helpful. Obviously if the EU doesn’t go in that direction that would be unhelpful.”

His spokesman denied that Mr Cameron returned empty-handed from the two-day meeting at the summer retreat of Fredrik Reinfeldt, the Swedish Prime Minister, also attended Mark Rutte, the Dutch Prime Minister.