Merkel urges Tories to stay in EPP group

The new German chancellor Angela Merkel made clear her displeasure over such a move.

In a letter to Mr Cameron she wrote "I look forward to good and intensive co-operation with you, in particular within the framework of the EPP-ED as a clear base for our bilateral dialogue as partners".

She also urged Mr Cameron to place Britain at the heart of Europe, indicating in her letter that "Great Britain and the British Conservatives are an indisputable element of European politics".

But while European conservative party leaders were gathering in Meise outside Brussels to prepare for the EU summit, Mr Cameron attended an event in Ulster, Northern Ireland.

The move fuelled immediate speculation of a possible split of the biggest political group in the European Parliament, the EPP-ED group.

"If Mr Cameron forces [the British conservatives] out of the EPP, he cannot expect high level contacts with the EPP. If someone intends to leave, this creates a clear distance", leader of the EPP-ED group Hans-Gert Pottering told reporters.

19 MEPs are needed to form a political group, and at least five member states must be represented within the group.

But not all Tory MEPs are happy leaving the EPP and forming a new centre-right anti-EU integration group in the European Parliament.

Right after David Cameron was elected party leader, the Tory MEPs re-elected Timothy Kirkhope as their leader with more than two thirds of the vote on what was described as a "stay-in-the-group" ticket.

The EPP brings together parties ruling ten of the current 25 EU member states, including Germany, France and Italy. The president of the commission, Jose Barroso, also belongs to the group.