A British Union flag and a European Union flag hang from a building behind a traffic sign in central London, Britain February 17, 2016. REUTERS/Toby Melville

LONDON (Reuters) - Support for Britain to leave the European Union stands at 45 percent, three points ahead of the “remain” camp, ahead of a referendum on June 23, according to an online opinion poll released on Tuesday by ICM.

The poll of 2,030 people, conducted between April 8 and 10, found that 12 percent of those surveyed were undecided.

ICM’s previous poll, released on April 6, had found that the “in” camp were ahead by one point on 43 percent.

“Most polls continue to suggest that it’s a very tight contest, with neither side able to gain a decisive lead,” said ICM’s Jennifer Bottomley on Tuesday.