Tories 'very disappointed' about teaming up with Merkel adversaries

Merkel had reportedly asked Cameron to prevent AfD from joining his MEPs in the ECR group. But his party members were outnumbered by Polish and other members of the ECR group.

A spokesman for the British Conservatives pointed to the very close vote: 29 in favour, 26 against the AfD membership. There are 19 Tory MEPs in the ECR group.

"We are very disappointed that AfD have been admitted into the ECR against our wishes. We note that the vote was a close one. We will work with the AfD in the European Parliament, but the CDU/CSU remains our only sister party in Germany," the spokesman said.

But Hans-Olaf Henkel, one of the leading figures in the AfD, praised the Tory MEPs for "supporting the AfD despite massive pressure from their leadership in London and despite massive intervention from Chancellor Merkel".

A spokesman for Chancellor Merkel in Berlin declined to comment on the ECR developments, which he deemed as "interesting, but in any case a political party matter".

Britain's Labour opposition interpreted the goings-on as weakening Cameron.

"Once again David Cameron's MEPs are undermining Britain's ability to reform the EU and their own prime minister's negotiating hand," said Glenis Willmott, the leader of Labour MEPs in the Parliament.

"At the time the British people need their politicians to be exerting influence in Europe, the Tories are isolating themselves from the mainstream," Willmott added.

When Cameron came to power in 2009, one of his first EU moves was to split from the federalist, centre-right European People's Party - the largest group in the European Parliament, dominated by Angela Merkel's Christian-Democrats (CDU/CSU).

Cameron needs Merkel's support in his opposition to Jean-Claude Juncker becoming the next commission president.

But at a retreat in Sweden earlier this week, Merkel restated her support for Juncker and said she does not like "threats" - a veiled reference to Cameron's warning that if Juncker gets the job, British people will have one more reason to vote for their country to leave the EU.

The ECR meanwhile might become the third-largest group after the EPP and the centre-left S&D. With the seven German deputies and a Bulgarian MEP, the ECR now has 63 MEPs.

The Liberals are on course to have 63 MEPs too, but ten of them are still uncertain. The cut-off date for MEPs joining groups is 24 June.

ECR members also voted for British MEP Syed Kamall to become chairman of the group, after their previous leader lost his seat in the May elections.

Kamall is the first Muslim to lead the group, which includes Danish and Finnish members who have expressed anti-Islam views in the past.