LONDON: A new opinion poll published today showed more Britons want to leave the European Union than want to stay ahead of a referendum to be held by 2017. The poll is the first to put the EU exit camp in the lead. Forty-three per cent of respondents said they would vote to leave, 40 per cent would vote to stay and 17 per cent are still undecided, according to the poll by Survation research agency for the right-wing Mail on Sunday newspaper. The survey, which was conducted online on September 3 and 4 and had 1,004 respondents, had a margin of error of two per centage points. Survation’s last poll published at the beginning of July showed 45 per cent in favour of staying, 37 per cent for leaving and 18 per cent undecided. Today’s poll also showed that 22 per cent of those who wanted Britain to stay said they could change their mind if the migrants crisis worsened. Twenty-nine per cent of respondents also told the pollsters that Britain should not accept any more Syrian refugees — the highest response to a question on how many refugees Britain should take in. British lawmakers in the House of Commons are expected tomorrow to debate and vote on a draft bill to allow the referendum, which will then pass to the House of Lords for final approval. Prime Minister David Cameron has said he will campaign to stay in the European Union only as long as he can negotiate a series of EU reforms intended to restore more sovereignty powers to Britain.