Baku, October 25 (AZERTAC). Parliament rejected a call for a referendum on leaving the European Union on Monday, but a large-scale revolt against Prime Minister David Cameron hurt his authority and cast doubt on the country`s long-term commitment to Europe.

Around 80 members of Cameron`s Conservative Party -- more than a quarter of the total -- defied their leader by voting for the motion, the biggest revolt against a Conservative prime minister on a European issue.

"We understand that many people who voted for it felt very strongly -- and we respect that. However, the government has to do what is in the national interest .... Britain`s best interests are served by being in the EU," a statement from Cameron`s office said after the vote.

The motion carried no legal weight, but the rebellion, the biggest of Cameron`s 17-month old government, raised the prospect of a return of Conservative divisions over Europe that dogged former Prime Minister John Major in the 1990s.

Cameron had ordered his predominantly eurosceptic Conservative Party to reject the motion, arguing that Britain needs a strong voice in Europe to safeguard its interests as the euro zone tackles a debt crisis.

The disunity embarrasses the prime minister and weakens his hand as he fights to keep Britain at the forefront of talks to reform the euro zone. Cameron wants Britain to remain in the EU while clawing back powers from Brussels.

He is due to attend an emergency European Council meeting on the euro zone crisis on Wednesday.

"It`s obviously a major embarrassment .... the key thing is whether they`re going to start rebelling on other issues as well, then that really turn the drama into a crisis," said Tim Bale, politics professor at Sussex University, adding that there was no sign of further rebellions so far.

"I would have thought there will be some partners in Europe who will be concerned about Britain`s long-term commitment to the EU as a whole because of this," he said.

After more than five hours of fractious debate, the referendum call was easily defeated by 483-111 thanks to votes against from the Conservatives` pro-European Liberal Democrat coalition partners and opposition Labour politicians.

Supporters of EU membership say Britain does 40 percent of its trade with the euro zone and that leaving the EU could damage the economy.

Eurosceptics dismiss such fears, and say Britain has handed too many powers to the European Union, which they see as undemocratic, over-regulated and a brake on economic growth.

Cameron thought he had done enough to pacify hardline eurosceptics by passing a law promising that no further powers would be transferred from London to Brussels without a referendum, but Monday`s vote shows it does not go far enough.

The euro zone crisis has created a dilemma for Cameron`s government, which does not want to stump up much money for a euro zone bailout. However, it fears the euro zone could exclude it from decisions on things that matter to Britain, particularly the financial services industry, where London dominates.

Opposition Labour Party leader Ed Miliband labelled the Conservative fissures as a "re-run of the old movie of the out-of-touch Tory (Conservative) Party tearing itself apart over Europe."

Conservative ministerial aide Adam Holloway indicated he was prepared to quit to back the motion, which was triggered by a public petition of more than 100,000 people. At least one other ministerial aide said they were also prepared to risk their job.

"This was such a critical thing really in terms of my reputation, and my relationship with my constituents that I didn`t really have a choice," Holloway told the BBC.