British Prime Minister David Cameron has signalled his determination to face down a backbench Conservative revolt over Europe by moving a high-profile debate to allow key ministers to take part, officials said Thursday.A House of Commons vote on whether to stage a referendum on Britain\'s future in the European Union will now take place this Monday rather than next Thursday.Prime Minister David Cameron and Foreign Secretary William Hague were set to miss the showdown with eurosceptics because of a Commonwealth summit in Australia.The shift will allow Hague to spearhead the Government response and the premier to attend at least part of the debate amid mounting concerns of a significant rebellion, commentators said. Downing Street dismissed claims by critics that it had acted in a \"blind panic\" to counter mounting public backing for a vote.But party managers were reported to have told Number 10 that enforcing sufficient party discipline to prevent a sizeable rebellion could require the premier\'s presence.However, the chair of the influential Conservative backbench 1922 Committee, Graham Brady, urged Cameron to allow a free vote on the issue.There has been no official confirmation of whether Conservative MPs will be, as expected, subjected to a party discipline or a less stringent requirement.Cameron told MPs yesterday that a referendum was not \"the right answer\" for the UK and urged them not to seek one \"willy nilly\" at a time when there were other priorities.There may be \"opportunities\" for such a vote in the future if there were significant changes planned to the way the EU operated, he said.Writing in the Daily Telegraph newspaper today, Brady said \"What matters is that backbench MPs of all parties should be free to vote in accordance with our beliefs and in the interests of our constituents.\" House of Commons approval of the vote would give the Government \"an overwhelming mandate to seek the return of vital powers\" and \"allow voters to line up behind the Conservative policy of renegotiation\".The vote was ordered by the Backbench Business Committee after receiving a petition with more than 100,000 signatures.Supporters of a public vote, led by Conservative backbench MP David Nuttall, have tabled a motion calling for the country to be given a three-way choice between remaining in the EU, leaving or negotiating the terms of a looser relationship \"based on trade and co-operation\".Some 58 MPs, including 46 Conservatives, have so far signed the motion.Though the vote is not binding, approval from MPs would place enormous pressure on Cameron to respect the will of the Commons.A national poll would place enormous strain on the ruling coalition, as the Liberal Democrats are predominantly supportive of the EU, the commentators said.