David Cameron, the Conservative leader, today revealed his plans for pulling out of the European Parliament's biggest political group and instead forming a new coalition with the Czech Republic's ruling party.

In a move seen as a sop to his party's eurosceptic right, Mr Cameron confirmed that he would fulfil his leadership election commitment to quit the European People's Party (EPP). Some right-wing MPs view the EPP's federalist views as incompatible with Conservative policy.

Mr Cameron said that he expects his party's 26 Euro MPs to join the coalition with the Czech Civic Democratic Party, described by one Tory politician as "identikit Tories except that they don't understand cricket". The union is not expected to take place until 2009, which led to accusations from Liberal Democrats in the European Parliament that the Tory leader was flip-flopping on his pledge to leave the EPP immediately.

However, the Tory leader will hope the delay will help to appease a minority of his Euro MPs who have said they would risk deselection rather than leave the EPP.

Mr Cameron made the annoucement to MPs in the House of Commons today and was later due to sign a joint declaration with Czech Prime Minister designate Mirek Topolanek. In a speech confirming the new grouping, he was expected to say that it was a simple choice to leave the EPP.

"While we agree about open markets and deregulation, we don’t share their views about the future development of Europe. We have no time for the culture of hopelessness that has plagued the way the European Union addresses the big global challenges we face," Mr Cameron will say.

But Diana Wallis MEP, the Liberal Democrat leader in the European Parliament, said the supposed compromise would satisfy neither euro-sceptics nor cheerleaders for Europe.

She said: "David Cameron made one specific pledge during his leadership campaign and that was to leave the EPP as soon as possible - within months we were told.

"If there are two things you can be sure about in this 'modern' Conservative party, it’s that David Cameron will flop-flop on any given issue, and that the party will never, ever stop arguing about Europe. This supposed compromise will probably please neither side. Any progressive, pro-European Conservative will always be welcome in the Liberal Democrats."

Last December, Chancellor Angela Merkel warned Mr Cameron against deserting the grouping, to which her Christian Democrats belong, saying it offered Germany’s governing party and Britain’s opposition opportunities for cooperation.