Poll predicts first UK parliament seat for anti-EU party in October 9 vote

LONDON (Reuters) - Britain's anti-EU UK Independence Party will easily win its first seat in the British parliament next month, an opinion poll suggested on Tuesday, after the ruling Conservative party named Oct. 9 as the date for a by-election in southern England. The seat, in Clacton, in the county of Essex, became vacant after Douglas Carswell, a lawmaker in Prime Minister David Cameron's Conservatives, unexpectedly defected to UKIP last month, saying he doubted Cameron's desire to reform the European Union. Cameron has pledged to try to reshape Britain's EU ties if re-elected before giving Britons an EU membership referendum. Next month's vote is seen as a test of UKIP's ability to damage the Conservatives at next May's national election amid public discontent about the government's failure to curb immigration and unease about Britain's membership of the EU. UKIP, which siphoned off Conservative votes to win European elections in Britain in May, wants the country to leave the EU and an end to "open door" immigration. An opinion poll published on Tuesday by Michael Ashcroft, a former deputy chairman of the Conservative party, put UKIP's support in Clacton on 56 percent, way ahead of the Conservatives on 24 percent. Ashcroft, who noted the election would happen on the same day as Cameron's birthday, said the result was not in doubt. "The Prime Minister’s birthday this year is unlikely to be his happiest, but at least he knows what he is going to get," said Ashcroft. "Even allowing for some movement in vote shares as the campaign unfolds over the next month, the likely outcome of the by-election is clear," Another opinion poll on Sunday suggested UKIP would also win a landslide victory at the seaside town in south-east England. (Reporting by William James; Editing by Stephen Addison and Andrew Osborn)