"Out" leads by 4 percentage points ahead of Britain's EU referendum - poll

A British Union flag and an European Union flag are seen flying above offices in London, Britain, March 30, 2016. REUTERS/Toby Melville/Files

LONDON (Reuters) - Support for Britain to leave the European Union stood at 43 percent, ahead of support to stay within the 28-member bloc, which stood at 39 percent, according to an online survey taken by pollster Opinium for the Observer newspaper. The poll of 1,966 adults, who were interviewed ahead of a referendum to stay in the European Union on June 23, found that 18 percent of respondents were undecided. (Reporting by Li-mei Hoang; Editing by Marguerita Choy)